Yellowstone National Park
Encyclopedia
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant
Ulysses S. Grant
Ulysses S. Grant was the 18th President of the United States as well as military commander during the Civil War and post-war Reconstruction periods. Under Grant's command, the Union Army defeated the Confederate military and ended the Confederate States of America...

 on March 1, 1872, is a national park
National park
A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...

 located primarily in the U.S. state of Wyoming, although it also extends into Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

 and Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

. Yellowstone was the first national park in the world, and is known for its wildlife and its many geothermal features
Geothermal areas of Yellowstone
The geothermal areas of Yellowstone include several geyser basins in Yellowstone National Park as well as other geothermal features such as hot springs, mud pots, and fumaroles...

, especially Old Faithful Geyser
Old Faithful Geyser
Old Faithful is a cone geyser located in Wyoming, in Yellowstone National Park in the United States. Old Faithful was named in 1870 during the Washburn-Langford-Doane Expedition and was the first geyser in the park to receive a name...

, one of the most popular features in the park. It has many types of ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

s, but the subalpine
Subalpine
The subalpine zone is the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.Trees in the...

 forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

 is dominant.

Native Americans
Native Americans in the United States
Native Americans in the United States are the indigenous peoples in North America within the boundaries of the present-day continental United States, parts of Alaska, and the island state of Hawaii. They are composed of numerous, distinct tribes, states, and ethnic groups, many of which survive as...

 have lived in the Yellowstone region for at least 11,000 years. The region was bypassed during the Lewis and Clark Expedition
Lewis and Clark Expedition
The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...

 in the early 19th century. Aside from visits by mountain men
Mountain man
Mountain men were trappers and explorers who roamed the North American Rocky Mountains from about 1810 through the 1880s where they were instrumental in opening up the various Emigrant Trails allowing Americans in the east to settle the new territories of the far west by organized wagon trains...

 during the early-to-mid-19th century, organized exploration did not begin until the late 1860s. The U.S. Army was commissioned to oversee the park just after its establishment. In 1917, administration of the park was transferred to the National Park Service
National Park Service
The National Park Service is the U.S. federal agency that manages all national parks, many national monuments, and other conservation and historical properties with various title designations...

, which had been created the previous year. Hundreds of structures have been built and are protected for their architectural and historical significance, and researchers have examined more than 1,000 archaeological sites.

Yellowstone National Park spans an area of 3468.4 square miles (8,983.1 km²), comprising lakes, canyons, rivers and mountain range
Mountain range
A mountain range is a single, large mass consisting of a succession of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, direction, formation, and age; a component part of a mountain system or of a mountain chain...

s. Yellowstone Lake
Yellowstone Lake
Yellowstone Lake is the largest body of water in Yellowstone National Park, The lake is 7,732 feet above sea level and covers with 110 miles of shoreline. While the average depth of the lake is 139 feet its deepest spot is at least 390 feet...

 is one of the largest high-altitude lakes in North America and is centered over the Yellowstone Caldera
Yellowstone Caldera
The Yellowstone Caldera is the volcanic caldera located in Yellowstone National Park in the United States, sometimes referred to as the Yellowstone Supervolcano. The caldera is located in the northwest corner of Wyoming, in which the vast majority of the park is contained. The major features of...

, the largest supervolcano
Supervolcano
A supervolcano is a volcano capable of producing a volcanic eruption with an ejecta volume greater than 1,000 cubic kilometers . This is thousands of times larger than most historic volcanic eruptions. Supervolcanoes can occur when magma in the Earth rises into the crust from a hotspot but is...

 on the continent. The caldera is considered an active volcano. It has erupted with tremendous force several times in the last two million years. Half of the world's geothermal features are in Yellowstone, fueled by this ongoing volcanism. Lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

 flows and rocks from volcanic eruptions cover most of the land area of Yellowstone. The park is the centerpiece of the Greater Yellowstone Ecosystem
Greater Yellowstone Ecosystem
The Greater Yellowstone Ecosystem is one of the last remaining large, nearly intact ecosystems in the northern temperate zone of the Earth and is partly located in Yellowstone National Park. Conflict over management has been controversial, and the area is a flagship site among conservation groups...

, the largest remaining, nearly intact ecosystem in the Earth's northern temperate zone.

Hundreds of species of mammals, birds, fish and reptiles have been documented, including several that are either endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

 or threatened
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...

. The vast forests and grasslands also include unique species of plants. Yellowstone Park is the largest and most famous megafauna
Megafauna
In terrestrial zoology, megafauna are "giant", "very large" or "large" animals. The most common thresholds used are or...

 location in the Continental United States. Grizzly Bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...

s, wolves
Gray Wolf
The gray wolf , also known as the wolf, is the largest extant wild member of the Canidae family...

, and free-ranging herds of bison
American Bison
The American bison , also commonly known as the American buffalo, is a North American species of bison that once roamed the grasslands of North America in massive herds...

 and elk
Elk
The Elk is the large deer, also called Cervus canadensis or wapiti, of North America and eastern Asia.Elk may also refer to:Other antlered mammals:...

 live in the park. The Yellowstone Park Bison Herd
Yellowstone Park Bison Herd
The Yellowstone Park bison herd in Yellowstone National Park is probably the oldest and largest public bison herd in the United States of America. Yellowstone is known for its geothermal activity and large mammals, especially Elk, Wolves, American Bison, Bears, Pronghorn Antelope, Moose and Bighorn...

 is the oldest and largest public bison herd in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. Forest fires occur in the park each year; in the large forest fires of 1988
Yellowstone fires of 1988
The Yellowstone fires of 1988 together formed the largest wildfire in the recorded history of the U.S.'s Yellowstone National Park. Starting as many smaller individual fires, the flames spread quickly out of control with increasing winds and drought and combined into one large conflagration, which...

, nearly one third of the park burnt. Yellowstone has numerous recreational opportunities, including hiking
Hiking
Hiking is an outdoor activity which consists of walking in natural environments, often in mountainous or other scenic terrain. People often hike on hiking trails. It is such a popular activity that there are numerous hiking organizations worldwide. The health benefits of different types of hiking...

, camping
Camping
Camping is an outdoor recreational activity. The participants leave urban areas, their home region, or civilization and enjoy nature while spending one or several nights outdoors, usually at a campsite. Camping may involve the use of a tent, caravan, motorhome, cabin, a primitive structure, or no...

, boating
Boating
Boating is the leisurely activity of travelling by boat, or the recreational use of a boat whether powerboats, sailboats, or man-powered vessels , focused on the travel itself, as well as sports activities, such as fishing or water skiing...

, fishing
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....

 and sightseeing. Paved roads provide close access to the major geothermal areas as well as some of the lakes and waterfalls. During the winter, visitors often access the park by way of guided tours that use either snow coach
Snow coach
A snow coach is a specialized passenger transport vehicle, designed to operate over snow or ice, similar to alarge, multi-passenger snowcat that is equipped with bus style seating. These vehicles may have multiple sets of very large low pressure tires or they may have tracks...

es or snowmobile
Snowmobile
A snowmobile, also known in some places as a snowmachine, or sled,is a land vehicle for winter travel on snow. Designed to be operated on snow and ice, they require no road or trail. Design variations enable some machines to operate in deep snow or forests; most are used on open terrain, including...

.

History

The park is located at the headwaters of the Yellowstone River
Yellowstone River
The Yellowstone River is a tributary of the Missouri River, approximately long, in the western United States. Considered the principal tributary of the upper Missouri, the river and its tributaries drain a wide area stretching from the Rocky Mountains in the vicinity of the Yellowstone National...

, from which it takes its historical name. Near the end of the 18th century, French trappers
Coureur des bois
A coureur des bois or coureur de bois was an independent entrepreneurial French-Canadian woodsman who traveled in New France and the interior of North America. They travelled in the woods to trade various things for fur....

 named the river "Roche Jaune," which is probably a translation of the Minnetaree name "Mi tsi a-da-zi" (Rock Yellow River). Later, American trappers rendered the French name in English as "Yellow Stone." Although it is commonly believed that the river was named for the yellow rocks seen in the Grand Canyon of the Yellowstone
Grand Canyon of the Yellowstone
The Grand Canyon of the Yellowstone is the first large canyon on the Yellowstone River downstream from Yellowstone Falls in Yellowstone National Park...

, the Native American name source is not clear.

The human history of the park begins at least 11,000 years ago when aboriginal Americans first began to hunt and fish in the region. During the construction of the post office in Gardiner
Gardiner, Montana
Gardiner is a census-designated place in Park County, Montana, United States, along the 45th parallel. The population was 851 at the 2000 census....

, Montana, in the 1950s
1950s
The 1950s or The Fifties was the decade that began on January 1, 1950 and ended on December 31, 1959. The decade was the sixth decade of the 20th century...

, an obsidian projectile point of Clovis
Clovis culture
The Clovis culture is a prehistoric Paleo-Indian culture that first appears 11,500 RCYBP , at the end of the last glacial period, characterized by the manufacture of "Clovis points" and distinctive bone and ivory tools...

 origin was found that dated from approximately 11,000 years ago. These Paleo-Indians, of the Clovis culture, used the significant amounts of obsidian
Obsidian
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock.It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth...

 found in the park to make such cutting tool
Cutting tool
In the context of machining, a cutting tool is any tool that is used to remove material from the workpiece by means of shear deformation. Cutting may be accomplished by single-point or multipoint tools. Single-point tools are used in turning, shaping, plaining and similar operations, and remove...

s and weapon
Weapon
A weapon, arm, or armament is a tool or instrument used with the aim of causing damage or harm to living beings or artificial structures or systems...

s. Arrowhead
Arrowhead
An arrowhead is a tip, usually sharpened, added to an arrow to make it more deadly or to fulfill some special purpose. Historically arrowheads were made of stone and of organic materials; as human civilization progressed other materials were used...

s made of Yellowstone obsidian have been found as far away as the Mississippi Valley, indicating that a regular obsidian trade existed between local tribes and tribes farther east. By the time white
White people
White people is a term which usually refers to human beings characterized, at least in part, by the light pigmentation of their skin...

 explorers
Exploration
Exploration is the act of searching or traveling around a terrain for the purpose of discovery of resources or information. Exploration occurs in all non-sessile animal species, including humans...

 first entered the region during the Lewis and Clark Expedition
Lewis and Clark Expedition
The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...

 in 1805, they encountered the Nez Perce, Crow and Shoshone
Shoshone
The Shoshone or Shoshoni are a Native American tribe in the United States with three large divisions: the Northern, the Western and the Eastern....

 tribes. While passing through present day Montana, the expedition members were informed of the Yellowstone region to the south, but they did not investigate it.

In 1806, John Colter
John Colter
John Colter was a member of the Lewis and Clark Expedition . Though party to one of the more famous expeditions in history, Colter is best remembered for explorations he made during the winter of 1807–1808, when Colter became the first known person of European descent to enter the region now known...

, a member of the Lewis and Clark Expedition
Lewis and Clark Expedition
The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...

, left to join a group of fur trappers. After splitting up with the other trappers in 1807, Colter passed through a portion of what later became the park, during the winter of 1807–1808. He observed at least one geothermal area in the northeastern section of the park, near Tower Fall. After surviving wounds he suffered in a battle with members of the Crow and Blackfoot
Blackfoot
The Blackfoot Confederacy or Niitsítapi is the collective name of three First Nations in Alberta and one Native American tribe in Montana....

 tribes in 1809, he gave a description of a place of "fire and brimstone
Fire and brimstone
Fire and brimstone is an idiomatic expression of signs of God's wrath in the Hebrew Bible and the New Testament. In the Bible, they often appear in reference to the fate of the unfaithful. "Brimstone," possibly the ancient name for sulfur, evokes the acrid odor of volcanic activity...

" that was dismissed by most people as delirium. The supposedly imaginary place was nicknamed "Colter's Hell
Colter's Hell
Colter's Hell is an area of fumaroles and hot springs on the Shoshone River near Cody in the US state of Wyoming. The thermal area covers about a square mile at the mouth of the Shoshone's canyon. Its thermal activity has declined ever since its description by mountain man John Colter, who passed...

". Over the next forty years, numerous reports from mountain men and trappers told of boiling mud, steaming rivers and petrified
Petrifaction
In geology, petrifaction, petrification or silicification is the process by which organic material is converted into stone by impregnation with silica. It is a rare form of fossilization...

 trees, yet most of these reports were believed at the time to be myth.

After an 1856 exploration, mountain man Jim Bridger
Jim Bridger
James Felix "Jim" Bridger was among the foremost mountain men, trappers, scouts and guides who explored and trapped the Western United States during the decades of 1820-1850, as well as mediating between native tribes and encroaching whites...

 (also believed to be the first or second European American to have seen the Great Salt Lake
Great Salt Lake
The Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt water lake in the western hemisphere, the fourth-largest terminal lake in the world. In an average year the lake covers an area of around , but the lake's size fluctuates substantially due to its...

) reported observing boiling springs, spouting water, and a mountain of glass and yellow rock. These reports were largely ignored because Bridger was known for being a "spinner of yarns". In 1859, Captain William F. Raynolds
William F. Raynolds
William Franklin Raynolds was a U.S. Army Colonel, explorer, engineer, Mexican War and Civil War officer who is best known for leading the 1859-1860 Raynolds Expedition while serving as a member of the U.S. Army Corps of Topographical Engineers...

, U.S. Army surveyor embarked on a two year survey
Raynolds Expedition
The Raynolds Expedition was an United States Army exploring and mapping party which left St. Louis, Missouri May 29, 1859 and was intended to map the unexplored territory between Fort Pierre, Dakota Territory and headwaters of the Yellowstone River. Led by experienced explorer and topographical...

 of the northern Rockies. After wintering in Wyoming, in May 1860, Raynolds and his party which included naturalist Ferdinand Vandeveer Hayden
Ferdinand Vandeveer Hayden
Dr. Ferdinand Vandeveer Hayden was an American geologist noted for his pioneering surveying expeditions of the Rocky Mountains in the late 19th century. He was also a physician who served with the Union Army during the Civil War.-Early life:Ferdinand Hayden was born in Westfield, Massachusetts...

 and guide Jim Bridger attempted to cross the Continental Divide
Continental Divide
The Continental Divide of the Americas, or merely the Continental Gulf of Division or Great Divide, is the name given to the principal, and largely mountainous, hydrological divide of the Americas that separates the watersheds that drain into the Pacific Ocean from those river systems that drain...

 over Two Ocean Plateau from the Wind River
Wind River (Wyoming)
The Wind River is the name applied to the upper reaches of the Bighorn River in Wyoming in the United States. The Wind River is long. The two rivers are sometimes referred to as the Wind/Bighorn.-Course:...

 drainage in northwest Wyoming. Heavy spring snows prevented their passage but had they been able to traverse the divide, the party would have been the first organized survey to enter the Yellowstone region. The American Civil War
American Civil War
The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

 hampered further organized explorations until the late 1860s.
The first detailed expedition to the Yellowstone area was the Cook–Folsom–Peterson Expedition of 1869, which consisted of three privately funded explorers. The Folsom party followed the Yellowstone River to Yellowstone Lake. The members of the Folsom party kept a journal and based on the information it reported, a party of Montana residents organized the Washburn-Langford-Doane Expedition
Washburn-Langford-Doane Expedition
The Washburn Expedition of 1870, explored the region of northwestern Wyoming that a couple years later became Yellowstone National Park. Led by Henry Washburn, Nathaniel P. Langford and under U.S. Army escort led by Lt. Gustavus C...

 in 1870. It was headed by the surveyor-general of Montana Henry Washburn
Henry D. Washburn
Henry Dana Washburn was a U.S. Representative from Indiana and a general in the Union Army during the American Civil War.-Biography:...

, and included Nathaniel P. Langford
Nathaniel P. Langford
Nathaniel Pitt Langford was an explorer, businessman, bureaucrat, vigilante and historian from St. Paul, Minnesota who played an important role in the early years of the Montana gold fields, territorial government and the creation of Yellowstone National Park.-Montana Gold Fields:On June 16, 1862...

 (who later became known as "National Park" Langford) and a U.S. Army detachment commanded by Lt. Gustavus Doane
Gustavus Cheyney Doane
Gustavus Cheyney Doane was a U.S. Army Cavalry Captain, explorer, inventor and Civil War soldier who played a prominent role in the exploration of Yellowstone as a member of the Washburn-Langford-Doane Expedition.-Early life:...

.

The expedition spent about a month exploring the region, collecting specimens, and naming sites of interest. A Montana writer and lawyer named Cornelius Hedges, who had been a member of the Washburn expedition, proposed that the region should be set aside and protected as a National Park; he wrote a number of detailed articles about his observations for the Helena Herald newspaper between 1870 and 1871. Hedges essentially restated comments made in October 1865 by acting Montana Territorial Governor Thomas Francis Meagher
Thomas Francis Meagher
-Young Ireland:Meagher returned to Ireland in 1843, with undecided plans for a career in the Austrian army, a tradition among a number of Irish families. In 1844 he traveled to Dublin with the intention of studying for the bar. He became involved in the Repeal Association, which worked for repeal...

, who had previously commented that the region should be protected. Others made similar suggestions. In an 1871 letter from Jay Cooke
Jay Cooke
Jay Cooke was an American financier. Cooke and his firm Jay Cooke & Company were most notable for their role in financing the Union's war effort during the American Civil War...

 to Ferdinand Hayden, Cooke wrote that his friend, Congressman William D. Kelley
William D. Kelley
William D. Kelley was a Republican member of the U.S. House of Representatives from Pennsylvania. Kelley was a lifelong advocate of civil rights, social reform, and labor protection.-Early life:...

 had also suggested "Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

 pass a bill reserving the Great Geyser Basin as a public park forever".

Park creation

In 1871, eleven years after his failed first effort, F.V. Hayden was finally able to make another attempt to explore the region. With government sponsorship, Hayden returned to Yellowstone region with a second, larger expedition, the Hayden Geological Survey of 1871
Hayden Geological Survey of 1871
The Hayden Geological Survey of 1871 explored the region of northwestern Wyoming that later became Yellowstone National Park in 1872. It was led by geologist Ferdinand Vandeveer Hayden...

. He compiled a comprehensive report on Yellowstone, which included large-format photographs by William Henry Jackson
William Henry Jackson
William Henry Jackson was an American painter, Civil War, geological survey photographer and an explorer famous for his images of the American West...

, as well as paintings by Thomas Moran
Thomas Moran
Thomas Moran from Bolton, England was an American painter and printmaker of the Hudson River School in New York whose work often featured the Rocky Mountains. Moran and his family took residence in New York where he obtained work as an artist...

. His report helped to convince the U.S. Congress to withdraw this region from public auction
Public auction
A public auction is an auction held on behalf of a government in which the property to be auctioned is either property owned by the government, or property which is sold under the authority of a court of law or a government agency with similar authority....

. On March 1, 1872, President Ulysses S. Grant
Ulysses S. Grant
Ulysses S. Grant was the 18th President of the United States as well as military commander during the Civil War and post-war Reconstruction periods. Under Grant's command, the Union Army defeated the Confederate military and ended the Confederate States of America...

 signed The Act of Dedication law that created Yellowstone National Park.

Ferdinand V. Hayden, while not the only person to have thought of creating a park in the Yellowstone region, was the park's first and most enthusiastic advocate. He believed in “setting aside the area as a pleasure ground for the benefit and enjoyment of the people” and warned that there were those who would come and “make merchandise of these beautiful specimens”. Worrying the area could face the same fate as Niagara Falls
Niagara Falls
The Niagara Falls, located on the Niagara River draining Lake Erie into Lake Ontario, is the collective name for the Horseshoe Falls and the adjacent American Falls along with the comparatively small Bridal Veil Falls, which combined form the highest flow rate of any waterfalls in the world and has...

, he concluded the site should “be as free as the air or Water.” In his report to the Committee on Public Lands, he concluded that if the bill failed to become law, “the vandals who are now waiting to enter into this wonder-land, will in a single season despoil, beyond recovery, these remarkable curiosities, which have requited all the cunning skill of nature thousands of years to prepare”. Hayden and his 1871 party recognized that Yellowstone was a priceless treasure, which would become rarer with time. He wished for others to see and experience it as well. Eventually the railroads and, some time after that, the automobile would make that possible. The Park was not set aside strictly for ecological purposes; however, the designation “pleasure ground” was not an invitation to create an amusement park. Hayden imagined something akin to the scenic resorts and baths in England, Germany and Switzerland.


THE ACT OF DEDICATION



AN ACT to set apart a certain tract of land lying near the headwaters of the Yellowstone River as a public park. Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That the tract of land in the Territories of Montana and Wyoming .... is hereby reserved and withdrawn from settlement, occupancy, or sale under the laws of the United States, and dedicated and set apart as a public park or pleasuring ground for the benefit and enjoyment of the people; and all persons who shall locate, or settle upon, or occupy the same or any part thereof, except as hereinafter provided, shall be considered trespassers and removed there from...


Approved March 1, 1872.



Signed by:
  • JAMES G. BLAINE
    James G. Blaine
    James Gillespie Blaine was a U.S. Representative, Speaker of the United States House of Representatives, U.S. Senator from Maine, two-time Secretary of State...

    , Speaker of the House.
  • SCHUYLER COLFAX
    Schuyler Colfax
    Schuyler Colfax, Jr. was a United States Representative from Indiana , Speaker of the House of Representatives , and the 17th Vice President of the United States . To date, he is one of only two Americans to have served as both House speaker and vice president.President Ulysses S...

    , Vice-President of the United States and President of the Senate.
  • ULYSSES S. GRANT
    Ulysses S. Grant
    Ulysses S. Grant was the 18th President of the United States as well as military commander during the Civil War and post-war Reconstruction periods. Under Grant's command, the Union Army defeated the Confederate military and ended the Confederate States of America...

    , President of the United States.



There was considerable local opposition to the Yellowstone National Park during its early years: some locals feared that the regional economy would be unable to thrive if there remained strict federal prohibitions against resource development or settlement within park boundaries; local entrepreneurs advocated reducing the size of the park so that mining, hunting, and logging activities could be developed and numerous bills were introduced into Congress by Montana representatives who sought to remove the federal land-use restrictions.

After the park's official formation, Nathaniel Langford was appointed as the park's first superintendent in 1872. He served for five years but was denied a salary, funding, and staff. Langford lacked the means to improve the land or properly protect the park, and without formal policy or regulations, he had few legal methods to enforce such protection. This left Yellowstone vulnerable to poachers, vandals, and others seeking to raid its resources. He addressed the practical problems park administrators faced in the 1872 Report to the Secretary of the Interior and correctly predicted that Yellowstone will become a major international attraction deserving the continuing stewardship of the government. In 1875, Colonel William Ludlow
William Ludlow
William Ludlow was an officer in the Corps of Engineers and a major general in the United States Army who served in the Civil War, Plains Indian Wars, the Spanish-American War, and led a scientific expedition examining the natural wonders of Yellowstone National Park.-Early life:Ludlow was born in...

, who had previously explored areas of Montana under the command of George Armstrong Custer
George Armstrong Custer
George Armstrong Custer was a United States Army officer and cavalry commander in the American Civil War and the Indian Wars. Raised in Michigan and Ohio, Custer was admitted to West Point in 1858, where he graduated last in his class...

, was assigned to organize and lead an expedition to Montana and the newly established Yellowstone Park. Observations about the lawlessness and exploitation of park resources were included in Ludlow's Report of a Reconnaissance to the Yellowstone National Park. The report included letters and attachments by other expedition members, including naturalist and mineralogist George Bird Grinnell
George Bird Grinnell
George Bird Grinnell was an American anthropologist, historian, naturalist, and writer. Grinnell was born in Brooklyn, New York, and graduated from Yale University with a B.A. in 1870 and a Ph.D. in 1880. Originally specializing in zoology, he became a prominent early conservationist and student...

. Grinnell documented the poaching of buffalo, deer, elk and antelope for hides. "It is estimated that during the winter of 1874–1875, not less than 3,000 buffalo and mule deer suffer even more severely than the elk, and the antelope nearly as much."

As a result, Langford was forced to step down in 1877.
Having traveled through Yellowstone and witnessed land management problems first hand, Philetus Norris
Philetus Norris
Philetus W. Norris was the second superintendent of Yellowstone National Park and was the first person to be paid for that position.- Early life :...

 volunteered for the position following Langford's exit. Congress finally saw fit to implement a salary for the position, as well as to provide a minimal funding to operate the park. Norris used these funds to expand access to the park, building numerous crude roads and facilities.

In 1880, Harry Yount
Harry Yount
Henry S. Yount was an American Civil War soldier, mountain man, professional hunter and trapper, prospector, wilderness guide and packer, seasonal employee of the United States Department of the Interior, and the first gamekeeper in Yellowstone National Park...

 was appointed as a gamekeeper to control poaching and vandalism in the park. Yount had previously spent a number of years exploring the mountain country of present-day Wyoming, including the Grand Tetons, after joining Dr. Hayden’s Geological Survey in 1873.
Today, he is considered the first national park ranger, and Younts Peak, located at the head of the Yellowstone River, was named in his honor. However, these measures still proved to be insufficient in protecting the park, as neither Norris, nor the three superintendents who followed, were given sufficient manpower or resources.
The Northern Pacific Railroad built a train station
Train station
A train station, also called a railroad station or railway station and often shortened to just station,"Station" is commonly understood to mean "train station" unless otherwise qualified. This is evident from dictionary entries e.g...

 in Livingston
Livingston, Montana
-Geography:Livingston is located at , at an altitude of 4.501 feet .According to the United States Census Bureau, the city has a total area of , of which, of it is land and 0.38% is waters.-Climate:-Demographics:...

, Montana, connecting to the northern entrance in the early 1880s, which helped to increase visitation from 300 in 1872 to 5,000 in 1883. Visitors in these early years were faced with poor roads and limited services, and most access into the park was on horse or via stagecoach
Stagecoach
A stagecoach is a type of covered wagon for passengers and goods, strongly sprung and drawn by four horses, usually four-in-hand. Widely used before the introduction of railway transport, it made regular trips between stages or stations, which were places of rest provided for stagecoach travelers...

. By 1908 visitation increased enough to also attract a Union Pacific Railroad
Union Pacific Railroad
The Union Pacific Railroad , headquartered in Omaha, Nebraska, is the largest railroad network in the United States. James R. Young is president, CEO and Chairman....

 connection to West Yellowstone, though rail visitation fell off considerably by World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 and ceased around the 1960s. Much of the railroad line was converted to nature trails, among them the Yellowstone Branch Line Trail.
During the 1870s and 1880s Native American
Native Americans in the United States
Native Americans in the United States are the indigenous peoples in North America within the boundaries of the present-day continental United States, parts of Alaska, and the island state of Hawaii. They are composed of numerous, distinct tribes, states, and ethnic groups, many of which survive as...

 tribes were effectively excluded from the national park. A number of tribes had made seasonal use of the Yellowstone area, but the only year-round residents were small bands of Western Shoshone
Shoshone
The Shoshone or Shoshoni are a Native American tribe in the United States with three large divisions: the Northern, the Western and the Eastern....

 known as "Sheepeaters". They left the area under the assurances of a treaty negotiated in 1868, under which the Sheepeaters ceded their lands but retained the right to hunt in Yellowstone. The United States never ratified the treaty and refused to recognize the claims of the Sheepeaters or any other tribe that had made use of Yellowstone. The Nez Perce band associated with Chief Joseph
Chief Joseph
Hin-mah-too-yah-lat-kekt, popularly known as Chief Joseph, or Young Joseph was the leader of the Wal-lam-wat-kain band of Nez Perce during General Oliver O. Howard's attempt to forcibly remove his band and the other "non-treaty" Nez Perce to a reservation in Idaho...

, numbering about 750 people, passed through Yellowstone National Park in thirteen days during late August, 1877. They were being pursued by the U.S. Army and entered the national park about two weeks after the Battle of the Big Hole
Battle of the Big Hole
The Battle of the Big Hole was a costly battle in the Montana Territory between the Nez Percé and United States army during the Nez Perce War of 1877.-Background:...

. Some of the Nez Perce were friendly to the tourists and other people they encountered in the park, some were not. Nine park visitors were briefly taken captive. Despite Joseph and other chiefs ordering that no one should be harmed, at least two people were killed and several wounded. One of the areas where encounters occurred was in Lower Geyser Basin and east along a branch of the Firehole River to Mary Mountain and beyond. That stream is still known as Nez Perce Creek. A group of Bannocks
Bannock (tribe)
The Bannock tribe of the Northern Paiute are an indigenous people of the Great Basin. Their traditional lands include southeastern Oregon, southeastern Idaho, western Wyoming, and southwestern Montana...

 entered the park in 1878, alarming park Superintendent Philetus Norris
Philetus Norris
Philetus W. Norris was the second superintendent of Yellowstone National Park and was the first person to be paid for that position.- Early life :...

. In the aftermath of the Sheepeater Indian War
Sheepeater Indian War
The Sheepeater Indian War of 1879 was the last Indian war fought in the Pacific Northwest portion of the United States. A band of approximately 300 Western Shoshone, , were known as the Sheepeaters because of their proficiency in hunting Rocky Mountain sheep...

 of 1879, Norris built a fort for the purpose of preventing Native Americans from entering the national park.

Ongoing poaching and destruction of natural resources continued unabated until the U.S. Army arrived at Mammoth Hot Springs
Mammoth Hot Springs
Mammoth Hot Springs is a large complex of hot springs on a hill of travertine in Yellowstone National Park adjacent to Fort Yellowstone and the Mammoth Hot Springs Historic District. It was created over thousands of years as hot water from the spring cooled and deposited calcium carbonate...

 in 1886 and built Camp Sheridan. Over the next 22 years the army constructed permanent structures, and Camp Sheridan was renamed Fort Yellowstone
Fort Yellowstone
-See also:* Grand Loop Road Historic District* Lake Fish Hatchery Historic District* Mammoth Hot Springs Historic District* North Entrance Road Historic District* Roosevelt Lodge Historic District* Old Faithful Historic District* US Post Office-Yellowstone Main...

. With the funding and manpower necessary to keep a diligent watch, the army developed their own policies and regulations that permitted public access while protecting park wildlife and natural resources. When the National Park Service was created in 1916, many of the management principles developed by the army were adopted by the new agency. The army turned control over to the National Park Service on October 31, 1918.

Later history

By 1915, 1,000 automobiles per year were entering the park, resulting in conflicts with horses and horse driven transportation. In subsequent years horse travel on roads was eventually prohibited. Between 1933 and 1941, the Civilian Conservation Corps
Civilian Conservation Corps
The Civilian Conservation Corps was a public work relief program that operated from 1933 to 1942 in the United States for unemployed, unmarried men from relief families, ages 18–25. A part of the New Deal of President Franklin D...

 built the majority of the early visitor centers, campgrounds and the current system of park roads. During World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, staffing and visitation both decreased, and many facilities fell into disrepair. By the 1950s, visitation increased tremendously in Yellowstone and other national parks. To accommodate the increased visitation, park officials implemented Mission 66
Mission 66
Mission 66 was a US National Park Service ten-year program that was intended to dramatically expand Park Service visitor services by 1966, in time for the 50th anniversary of the establishment of the Park Service....

, an effort to modernize and expand park service facilities. Planned to be completed by 1966, in honor of the 50th anniversary of the founding of the National Park Service, Mission 66 construction diverged from the traditional log cabin style with design features of a modern style. During the late 1980s, most construction styles in Yellowstone reverted back to the more traditional designs. After the enormous forest fires of 1988 damaged much of Grant Village, structures there were rebuilt in the traditional style. The visitor center at Canyon Village, which opened in 2006, incorporates a more traditional design as well.
The 1959 Yellowstone earthquake
1959 Yellowstone earthquake
The 1959 Yellowstone earthquake also known as the Hebgen Lake earthquake was a powerful earthquake that occurred on August 17, 1959 at 11:37 pm in southwestern Montana. The earthquake was registered at magnitude 7.3 – 7.5 on the Richter scale...

 just west of Yellowstone at Hebgen Lake
Hebgen Lake
Hebgen Lake is a lake located in Southwest Montana and is created by Hebgen Dam. It is well known for a magnitude 7.5 earthquake which occurred nearby on August 17, 1959, forming Quake Lake which is located immediately downstream.-Recreation:...

 damaged roads and some structures in the park. In the northwest section of the park, new geysers were found, and many existing hot springs became turbid. It was the most powerful earthquake to hit the region in recorded history. In 1963, after several years of public controversy regarding the forced reduction of the elk population in Yellowstone, United States Secretary of the Interior
United States Secretary of the Interior
The United States Secretary of the Interior is the head of the United States Department of the Interior.The US Department of the Interior should not be confused with the concept of Ministries of the Interior as used in other countries...

 Stewart Udall
Stewart Udall
Stewart Lee Udall was an American politician. After serving three terms as a congressman from Arizona, he served as Secretary of the Interior from 1961 to 1969, under Presidents John F. Kennedy and Lyndon B...

 appointed an advisory board to collect scientific data to inform future wildlife management of the national parks. In a paper known as the Leopold Report
Leopold Report
The Leopold Report, officially known as Wildlife Management in the National Parks, is a 1963 paper composed of a series of ecosystem management recommendations that were presented by the Special Advisory Board on Wildlife Management to United States Secretary of the Interior Stewart Udall. Named...

, the committee observed that culling programs at other national parks had been ineffective, and recommended management of Yellowstone's elk population.

The wildfire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...

s during the summer of 1988 were the largest in the history of the park. Approximately 793880 acre (321,272 ha; 1,240 sq mi) or 36% of the parkland was impacted by the fires, leading to a systematic reevaluation of fire management policies. The fire season of 1988 was considered normal until a combination of drought and heat by mid-July contributed to an extreme fire danger. On "Black Saturday," August 20, 1988, strong winds expanded the fires rapidly, and more than 150000 acre (60,702.9 ha; 234.4 sq mi) burned.

The expansive cultural history of the park has been documented by the 1,000 archeological sites that have been discovered. The park has 1,106 historic structures
National Register of Historic Places listings in Yellowstone National Park
This is a list of the National Register of Historic Places listings in Yellowstone National Park.This is intended to be a complete list of the properties and districts on the National Register of Historic Places in Yellowstone National Park, Wyoming and Montana, United States...

 and features, and of these Obsidian Cliff
Obsidian Cliff
Obsidian Cliff, also known as 48YE433, was an important source of lithic materials for prehistoric peoples in Yellowstone National Park near Gardiner, Montana. The cliff was named by Philetus Norris, the second park superintendent in 1878. It was declared a National Historic Landmark in 1996.The...

 and five buildings have been designated National Historic Landmarks. Yellowstone was designated an International Biosphere Reserve on October 26, 1976, and a United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...

 World Heritage Site
World Heritage Site
A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...

 on September 8, 1978.

In 2010, Yellowstone National Park was honored with its own quarter under the America the Beautiful Quarters Program.

Heritage & Research Center

The Heritage & Research Center is located at Gardiner, Montana, near the north entrance to the park. The center is home to the Yellowstone National Park’s museum collection, archives, research library, historian, archeology lab, and herbarium. The Yellowstone National Park Archives maintain collections of historical records of Yellowstone and the National Park Service. The collection includes the administrative records of Yellowstone, the world’s first national park, as well as resource management records, records from major projects, and donated manuscripts and personal papers. The archives are affiliated with the National Archives and Records Administration
National Archives and Records Administration
The National Archives and Records Administration is an independent agency of the United States government charged with preserving and documenting government and historical records and with increasing public access to those documents, which comprise the National Archives...

.

Geography

Approximately 96 percent of the land area of Yellowstone National Park is located within the state of Wyoming. Another 3 percent is within Montana, with the remaining 1 percent in Idaho. The park is 63 miles (101.4 km) north to south, and 54 miles (86.9 km) west to east by air. Yellowstone is 2219789 acre (898,317.5 ha; 3,468.4 sq mi) in area, larger than the states of Rhode Island
Rhode Island
The state of Rhode Island and Providence Plantations, more commonly referred to as Rhode Island , is a state in the New England region of the United States. It is the smallest U.S. state by area...

 or Delaware
Delaware
Delaware is a U.S. state located on the Atlantic Coast in the Mid-Atlantic region of the United States. It is bordered to the south and west by Maryland, and to the north by Pennsylvania...

. Rivers and lakes cover 5 percent of the land area, with the largest water body being Yellowstone Lake at 87040 acre (35,223.9 ha; 136 sq mi). Yellowstone Lake is up to 400 feet (121.9 m) deep and has 110 miles (177 km) of shoreline. At an elevation of 7733 feet (2,357 m) above sea level, Yellowstone Lake is the largest high altitude lake in North America. Forests comprise 80 percent of the land area of the park; most of the rest is grassland
Prairie
Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...

.

The Continental Divide
Continental Divide
The Continental Divide of the Americas, or merely the Continental Gulf of Division or Great Divide, is the name given to the principal, and largely mountainous, hydrological divide of the Americas that separates the watersheds that drain into the Pacific Ocean from those river systems that drain...

 of North America runs diagonally through the southwestern part of the park. The divide is a topographic
Topography
Topography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids...

 feature that separates Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 and Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

 water drainages. About one third of the park lies on the west side of the divide. The origins of the Yellowstone and Snake River
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...

s are near each other but on opposite sides of the divide. As a result, the waters of the Snake River flow to the Pacific Ocean, while those of the Yellowstone find their way to the Atlantic Ocean via the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...

.

The park sits on the Yellowstone Plateau
Yellowstone Plateau
The Yellowstone Plateau volcanic field is a geological feature found in the U.S. state of Wyoming. It is a popular site for tourists.The plateau developed through three volcanic cycles spanning two million years that included some of the world's largest known eruptions...

, at an average elevation of 8000 feet (2,438.4 m) above sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

. The plateau is bounded on nearly all sides by mountain range
Mountain range
A mountain range is a single, large mass consisting of a succession of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, direction, formation, and age; a component part of a mountain system or of a mountain chain...

s of the Middle Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

, which range from 9000 to 11000 ft (2,743.2 to 3,352.8 m) in elevation. The highest point in the park is atop Eagle Peak
Eagle Peak (Wyoming)
Eagle Peak is situated in the Absaroka Range in the U.S. state of Wyoming, and is the tallest mountain in Yellowstone National Park. Located on the park boundary with Shoshone National Forest, the mountain rises to the east of the southeast arm of Yellowstone Lake...

 (11358 feet (3,461.9 m)) and the lowest is along Reese Creek (5282 feet (1,610 m)). Nearby mountain ranges include the Gallatin Range
Gallatin Range
The Gallatin Range is located in the U.S. states of Montana and Wyoming and includes more than 10 mountains over . The highest peak in the range is Electric Peak at . The Gallatin Range was named after Albert Gallatin, the longest-serving US Secretary of the Treasury and one of the negotiators of...

 to the northwest, the Beartooth Mountains
Beartooth Mountains
The Beartooth Mountains are located in south central Montana and northwest Wyoming, U.S. and are part of the 900,000 acre Absaroka-Beartooth Wilderness, within Custer, Gallatin and Shoshone National Forests. The Beartooths are the location of Granite Peak, which at 12,807 feet is the highest...

 in the north, the Absaroka Range
Absaroka Range
The Absaroka Range is a sub-range of the Rocky Mountains in the United States. The range stretches about 150 mi across the Montana-Wyoming border, forming the eastern boundary of Yellowstone National Park and the western side of the Bighorn Basin. The range borders the Beartooth Mountains...

 to the east, and the Teton Range
Teton Range
The Teton Range is a mountain range of the Rocky Mountains in North America. A north-south range, it is on the Wyoming side of the state's border with Idaho, just south of Yellowstone National Park. Most of the range is in Grand Teton National Park....

 and the Madison Range
Madison Range
The Madison Range is a mountain range located in the Rocky Mountains of Montana and Idaho, U.S. The range was named in honor of future President of the United States, then U.S. Secretary of State James Madison by Meriwether Lewis as the Lewis and Clark Expedition travelled through Montana in 1805...

 to the southwest and west. The most prominent summit on the Yellowstone Plateau is Mount Washburn
Mount Washburn
Mount Washburn el. is a prominent mountain peak in the Washburn Range in Yellowstone National Park, Wyoming. The peak was named in 1870 to honor Henry D. Washburn, leader of the Washburn–Langford–Doane Expedition...

 at 10243 feet (3,122.1 m).

Yellowstone National Park has one of the world's largest petrified forest
Petrified Forest
A petrified forest is a forest in which tree trunks have fossilized as petrified wood.Petrified Forest may refer to:*Lake Macquarie Petrified Forest, Lake Macquarie, New South Wales, Australia*Mississippi Petrified Forest, Mississippi, United States...

s, trees which were long ago buried by ash and soil and transformed from wood to mineral materials. This ash and other volcanic debris, are believed to have come from the park area itself. This is largely due to the fact that Yellowstone is actually a massive caldera of a supervolcano. There are 290 waterfall
Waterfall
A waterfall is a place where flowing water rapidly drops in elevation as it flows over a steep region or a cliff.-Formation:Waterfalls are commonly formed when a river is young. At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens...

s of at least 15 feet (4.6 m) in the park, the highest being the Lower Falls of the Yellowstone River
Yellowstone Falls
Yellowstone Falls consist of two major waterfalls on the Yellowstone River, within Yellowstone National Park, Wyoming, United States. As the Yellowstone river flows north from Yellowstone Lake, it leaves the Hayden Valley and plunges first over Upper Yellowstone Falls and then a quarter mile ...

 at 308 feet (93.9 m).

Three deep canyons are located in the park, cut through the volcanic tuff of the Yellowstone Plateau by rivers over the last 640,000 years. The Lewis River
Lewis River (Wyoming)
The Lewis River is an tributary of the Snake River. The entire course of the river is located within the boundaries of Yellowstone National Park in Wyoming. The river is named for Meriwether Lewis, commander of the Lewis and Clark Expedition....

 flows through Lewis Canyon in the south, and the Yellowstone River
Yellowstone River
The Yellowstone River is a tributary of the Missouri River, approximately long, in the western United States. Considered the principal tributary of the upper Missouri, the river and its tributaries drain a wide area stretching from the Rocky Mountains in the vicinity of the Yellowstone National...

 has carved two colorful canyons, the Grand Canyon of the Yellowstone
Grand Canyon of the Yellowstone
The Grand Canyon of the Yellowstone is the first large canyon on the Yellowstone River downstream from Yellowstone Falls in Yellowstone National Park...

 and the Black Canyon of the Yellowstone in its journey north.

Geology

Yellowstone is at the northeastern end of the Snake River Plain
Snake River Plain
The Snake River Plain is a geologic feature located primarily within the state of Idaho in the United States of America. It stretches about westward from northwest of the state of Wyoming to the Idaho-Oregon border. The plain is a wide flat bow-shaped depression, and covers about a quarter of Idaho...

, a great U-shaped arc through the mountains that extends from Boise
Boise, Idaho
Boise is the capital and most populous city of the U.S. state of Idaho, as well as the county seat of Ada County. Located on the Boise River, it anchors the Boise City-Nampa metropolitan area and is the largest city between Salt Lake City, Utah and Portland, Oregon.As of the 2010 Census Bureau,...

, Idaho some 400 miles (643.7 km) to the west. This feature traces the route of the North American Plate
North American Plate
The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, Bahamas, and parts of Siberia, Japan and Iceland. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust...

 over the last 17 million years as it was transported by plate tectonics
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...

 across a stationary mantle
Mantle (geology)
The mantle is a part of a terrestrial planet or other rocky body large enough to have differentiation by density. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core....

 hotspot
Hotspot (geology)
The places known as hotspots or hot spots in geology are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the mantle elsewhere. They may be on, near to, or far from tectonic plate boundaries. There are two hypotheses to explain them...

. The landscape of present-day Yellowstone National Park is the most recent manifestation of this hotspot below the crust
Crust (geology)
In geology, the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle...

 of the Earth.

The Yellowstone Caldera
Yellowstone Caldera
The Yellowstone Caldera is the volcanic caldera located in Yellowstone National Park in the United States, sometimes referred to as the Yellowstone Supervolcano. The caldera is located in the northwest corner of Wyoming, in which the vast majority of the park is contained. The major features of...

 is the largest volcanic system in North America. It has been termed a "supervolcano
Supervolcano
A supervolcano is a volcano capable of producing a volcanic eruption with an ejecta volume greater than 1,000 cubic kilometers . This is thousands of times larger than most historic volcanic eruptions. Supervolcanoes can occur when magma in the Earth rises into the crust from a hotspot but is...

" because the caldera was formed by exceptionally large explosive eruptions. The current caldera was created by a cataclysmic eruption that occurred 640,000 years ago, which released 240 cubic miles (1,000 km³) of ash, rock and pyroclastic materials. This eruption was 1,000 times larger than the 1980 eruption of Mount St. Helens
1980 eruption of Mount St. Helens
The 1980 eruption of Mount St. Helens, a stratovolcano located in Washington state, in the United States, was a major volcanic eruption. The eruption was the only significant one to occur in the contiguous 48 U.S. states since the 1915 eruption of Lassen Peak in California...

. It produced a crater
Volcanic crater
A volcanic crater is a circular depression in the ground caused by volcanic activity. It is typically a basin, circular in form within which occurs a vent from which magma erupts as gases, lava, and ejecta. A crater can be of large dimensions, and sometimes of great depth...

 nearly a two thirds of a mile (1 km) deep and 52 by in area and deposited the Lava Creek Tuff
Lava Creek Tuff
Lava Creek Tuff is a tuff formation, in Wyoming, created when the Yellowstone Caldera erupted about 640,000 years ago.The Lava Creek Tuff distributed in a radial pattern around the caldera and is formed of of ash in pyroclastic flows....

, a welded tuff geologic formation
Geologic formation
A formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...

. The most violent known eruption, which occurred 2.1 million years ago, ejected 588 cubic miles (2,450 km³) of volcanic material and created the rock formation known as the Huckleberry Ridge Tuff
Huckleberry Ridge Tuff
The Huckleberry Ridge Tuff is a tuff formation created by the Huckleberry Ridge eruption that formed the Island Park Caldera that lies partially in Yellowstone Park, Wyoming and stretches westward into Idaho into a region known as Island Park...

 and created the Island Park Caldera
Island Park Caldera
The volcanic feature commonly called the Island Park Caldera in the states of Idaho and Wyoming, U.S., is actually two calderas, one nested inside the other. The Island Park Caldera is the older and much larger caldera, with approximate dimensions of 58 miles by 40 miles...

. A smaller eruption ejected 67 cubic miles (280 km³) of material 1.2 million years ago, forming the Henry's Fork Caldera
Henry's Fork Caldera
The Henry's Fork Caldera in Idaho is a caldera located an area known as Island Park west of Yellowstone National Park. The caldera was formed by one of the world's supervolcanos in an eruption of more than 280 cubic kilometers 1.3 million years BP, and is the source of the Mesa Falls Tuff.The...

 and depositing the Mesa Falls Tuff
Mesa Falls Tuff
The Mesa Falls Tuff is a tuff formation created by the Mesa Falls eruption that formed the Henry's Fork Caldera that is located in Idaho west of Yellowstone Park. It is the second most recent caldera forming eruption from the Yellowstone hotspot and ejected of 280 km³ of material...

.
Each of the three climax eruptions released vast amounts of ash that blanketed much of central North America, falling many hundreds of miles away. The amount of ash and gases released into the atmosphere probably caused significant impacts to world weather patterns and led to the extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...

 of many species, primarily in North America.

A subsequent minor climax eruption occurred 160,000 years ago. It formed the relatively small caldera that contains the West Thumb of Yellowstone Lake. Later, two smaller eruptive cycles, the last one ending about 70,000 years ago, buried much of the caldera under thick lava flows.

Each eruption is in fact a part of an eruptive cycle that climaxes with the collapse of the roof of a partially emptied magma chamber
Magma chamber
A magma chamber is a large underground pool of molten rock found beneath the surface of the Earth. The molten rock in such a chamber is under great pressure, and given enough time, that pressure can gradually fracture the rock around it creating outlets for the magma...

. This creates a crater, called a caldera, and releases vast amounts of volcanic material, usually through fissures that ring the caldera. The time between the last three cataclysmic eruptions in the Yellowstone area has ranged from 600,000 to 900,000 years, but the small number of such climax eruptions cannot be used to make an accurate prediction for future volcanic events.

Between 630,000 and 700,000 years ago, Yellowstone Caldera was nearly filled in with periodic eruptions of rhyolitic
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...

 lavas such as those that can be seen at Obsidian Cliff
Obsidian Cliff
Obsidian Cliff, also known as 48YE433, was an important source of lithic materials for prehistoric peoples in Yellowstone National Park near Gardiner, Montana. The cliff was named by Philetus Norris, the second park superintendent in 1878. It was declared a National Historic Landmark in 1996.The...

s and basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

ic lavas which can be viewed at Sheepeater Cliff
Sheepeater Cliff
The Sheepeater Cliffs are a series of exposed cliffs made up of columnar basalt in Yellowstone National Park in the United States. The lava was deposited about 500,000 years ago during one of the periodic basaltic floods in Yellowstone Caldera, and later exposed by the Gardner River...

. Lava strata are most easily seen at the Grand Canyon of the Yellowstone, where the Yellowstone River continues to carve into the ancient lava flows. The canyon is a classic V-shaped valley, indicative of river-type erosion rather than erosion caused by glaciation
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

.

The most famous geyser
Geyser
A geyser is a spring characterized by intermittent discharge of water ejected turbulently and accompanied by a vapour phase . The word geyser comes from Geysir, the name of an erupting spring at Haukadalur, Iceland; that name, in turn, comes from the Icelandic verb geysa, "to gush", the verb...

 in the park, and perhaps the world, is Old Faithful Geyser
Old Faithful Geyser
Old Faithful is a cone geyser located in Wyoming, in Yellowstone National Park in the United States. Old Faithful was named in 1870 during the Washburn-Langford-Doane Expedition and was the first geyser in the park to receive a name...

, located in Upper Geyser Basin. Castle Geyser
Castle Geyser
Castle Geyser is a cone geyser in the Upper Geyser Basin of Yellowstone National Park. It is noted for the particularly large geyserite sinter deposits, which form its cone...

, Lion Geyser
Lion Geyser
Lion Geyser is a cone-type geyser in in the Upper Geyser Basin of Yellowstone National Park in the United States. It is located in the Geyser Hill complex....

 and Beehive Geyser
Beehive Geyser
Beehive Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States. The tall cone resembles a beehive. Beehive's Indicator is a small, jagged cone-type geyser located about from Beehive.-History:...

 are in the same basin. The park contains the largest active geyser in the world—Steamboat Geyser
Steamboat Geyser
Steamboat Geyser, in Yellowstone National Park's Norris Geyser Basin, is the world's tallest currently-active geyser. During major eruptions, water may be thrown more than 300 feet into the air....

 in the Norris Geyser Basin. There are 300 geysers in Yellowstone and a total of at least 10,000 geothermal features altogether. Half the geothermal features and two-thirds of the world's geysers are concentrated in Yellowstone.
In May 2001, the U.S. Geological Survey, Yellowstone National Park, and the University of Utah
University of Utah
The University of Utah, also known as the U or the U of U, is a public, coeducational research university in Salt Lake City, Utah, United States. The university was established in 1850 as the University of Deseret by the General Assembly of the provisional State of Deseret, making it Utah's oldest...

 created the Yellowstone Volcano Observatory (YVO), a partnership for long-term monitoring of the geological processes of the Yellowstone Plateau volcanic field, for disseminating information concerning the potential hazards of this geologically active region.
In 2003, changes at the Norris Geyser Basin resulted in the temporary closure of some trails in the basin. New fumarole
Fumarole
A fumarole is an opening in a planet's crust, often in the neighborhood of volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrogen sulfide. The steam is created when superheated water turns to steam as its pressure drops when it emerges from...

s were observed, and several geysers showed enhanced activity and increasing water temperatures. Several geysers became so hot that they were transformed into purely steaming features; the water had become superheated and they could no longer erupt normally. This coincided with the release of reports of a multiple year United States Geological Survey research project which mapped the bottom of Yellowstone Lake and identified a structural dome that had uplifted at some time in the past. Research indicated that these uplifts posed no immediate threat of a volcanic eruption, since they may have developed long ago, and there had been no temperature increase found near the uplifts. On March 10, 2004, a biologist discovered 5 dead bison which apparently had inhaled toxic geothermal gases trapped in the Norris Geyser Basin by a seasonal atmospheric inversion. This was closely followed by an upsurge of earthquake activity in April 2004. In 2006, it was reported that the Mallard Lake Dome and the Sour Creek Dome— areas that have long been known to show significant changes in their ground movement— had risen at a rate of 1.5 to 2.4 in (3.8 to 6.1 cm) per year from mid–2004 through 2006. As of late 2007, the uplift has continued at a reduced rate. These events inspired a great deal of media attention and speculation about the geologic future of the region. Experts responded to the conjecture by informing the public that there was no increased risk of a volcanic eruption in the near future.
Yellowstone experiences thousands of small earthquakes every year, virtually all of which are undetectable to people. There have been six earthquakes with at least magnitude
Moment magnitude scale
The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of...

 6 or greater in historical times, including a 7.5 magnitude quake that struck just outside the northwest boundary of the park in 1959. This quake triggered a huge landslide
Landslide
A landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments...

, which caused a partial dam collapse on Hebgen Lake
Hebgen Lake
Hebgen Lake is a lake located in Southwest Montana and is created by Hebgen Dam. It is well known for a magnitude 7.5 earthquake which occurred nearby on August 17, 1959, forming Quake Lake which is located immediately downstream.-Recreation:...

; immediately downstream, the sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....

 from the landslide dammed the river and created a new lake, known as Earthquake Lake
Quake Lake
Quake Lake is a lake in southwestern Montana, United States. It was created after a massive earthquake struck on August 17, 1959, which killed 27 people. Today, Quake Lake is 190 feet deep and six miles long...

. Twenty-eight people were killed, and property damage was extensive in the immediate region. The earthquake caused some geysers in the northwestern section of the park to erupt, large cracks in the ground formed and emitted steam, and some hot springs that normally have clear water turned muddy. A 6.1 magnitude earthquake struck inside the park on June 30, 1975, but damage was minimal. For three months in 1985, 3,000 minor earthquakes were detected in the northwestern section of the park, during what has been referred to as an earthquake swarm, and has been attributed to minor subsidence of the Yellowstone caldera. Beginning on April 30, 2007, sixteen small earthquakes with magnitudes up to 2.7 occurred in the Yellowstone Caldera for several days. These swarms of earthquakes are common, and there have been 70 such swarms between 1983 and 2008. In December 2008, over 250 earthquakes were measured over a four day span under Yellowstone Lake, the largest measuring a magnitude of 3.9. In January 2010, more than 250 earthquakes were detected over a two day period. Seismic activity in Yellowstone National Park continues and is reported hourly by the Earthquake Hazards Program of the U.S. Geological Survey.

Biology and ecology

Yellowstone National Park is the centerpiece of the 20 million acre/31,250 square-mile (8,093,712 ha/80,937 km2) Greater Yellowstone Ecosystem, a region that includes Grand Teton National Park
Grand Teton National Park
Grand Teton National Park is a United States National Park located in northwestern Wyoming, U.S. The Park consists of approximately and includes the major peaks of the long Teton Range as well as most of the northern sections of the valley known as Jackson Hole. Only south of Yellowstone...

, adjacent National Forests
United States National Forest
National Forest is a classification of federal lands in the United States.National Forests are largely forest and woodland areas owned by the federal government and managed by the United States Forest Service, part of the United States Department of Agriculture. Land management of these areas...

 and expansive wilderness
Wilderness
Wilderness or wildland is a natural environment on Earth that has not been significantly modified by human activity. It may also be defined as: "The most intact, undisturbed wild natural areas left on our planet—those last truly wild places that humans do not control and have not developed with...

 areas in those forests. The ecosystem is the largest remaining continuous stretch of mostly undeveloped pristine land in the continental United States,considered to be the world's largest intact ecosystem in the northern temperate zone (although the area is mostly not temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...

 but subalpine
Subalpine
The subalpine zone is the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.Trees in the...

, and all the national forest lands surrounding the National Park are not intact). With the successful wolf reintroduction
Wolf reintroduction
Wolf reintroduction involves the artificial reestablishment of a population of wolves in areas where they have been extirpated. Wolf reintroduction is only considered where large tracts of suitable wilderness still exist and where certain prey species are abundant enough to support a predetermined...

 program, which began in the 1990s, virtually all the original faunal species known to inhabit the region when white explorers first entered the area can still be found there.

Flora

Over 1,700 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

s and other vascular plant
Vascular plant
Vascular plants are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the clubmosses, Equisetum, ferns, gymnosperms and angiosperms...

s are native to the park. Another 170 species are considered to be exotic species and are non-native. Of the eight conifer tree species documented, Lodgepole Pine
Lodgepole Pine
Lodgepole Pine, Pinus contorta, also known as Shore Pine, is a common tree in western North America. Like all pines, it is evergreen.-Subspecies:...

 forests cover 80% of the total forested areas. Other conifers, such as Subalpine Fir
Subalpine Fir
The Subalpine Fir or Rocky Mountain Fir is a western North American fir, native to the mountains of Yukon, British Columbia and western Alberta in Canada; southeastern Alaska, Washington, Oregon, Idaho, western Montana, Wyoming, Utah, Colorado, New Mexico, Arizona, northeastern Nevada, and the...

, Engelmann Spruce
Engelmann Spruce
Picea engelmannii is a species of spruce native to western North America, from central British Columbia and southwest Alberta, southwest to northern California and southeast to Arizona and New Mexico; there are also two isolated populations in northern Mexico...

, Rocky Mountain Douglas-fir
Rocky Mountain Douglas-fir
The Rocky Mountain Douglas-fir, Pseudotsuga menziesii subsp. glauca, is an evergreen conifer native to the interior mountainous regions of western North America, from central British Columbia and southwest Alberta in Canada southward through the United States to the far north of Mexico...

 and Whitebark Pine
Whitebark Pine
Pinus albicaulis, known commonly as Whitebark Pine, Pitch Pine, Scrub Pine, and Creeping Pine occurs in the mountains of the Western United States and Canada, specifically the subalpine areas of the Sierra Nevada, the Cascade Range, the Pacific Coast Ranges, and the northern Rocky Mountains –...

, are found in scattered groves throughout the park. As of 2007, the whitebark pine is threatened by a fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...

 known as white pine blister rust
Cronartium ribicola
Cronartium ribicola is a species of rust fungi in the family Cronartiaceae that causes the disease white pine blister rust.Like many other rusts, C. ribicola is heteroecious, meaning it requires two host species to complete its lifecycle that includes five spore stages...

; however, this is mostly confined to forests well to the north and west. In Yellowstone, about seven percent of the whitebark pine species have been impacted with the fungus, compared to nearly complete infestations in northwestern Montana. Quaking Aspen and willow
Willow
Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...

s are the most common species of deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

 trees. The aspen forests have declined significantly since the early 20th century, but scientists at Oregon State University attribute recent recovery of the aspen to the reintroduction of wolves which has changed the grazing habits of local elk.
There are dozens of species of flowering plants that have been identified, most of which bloom between the months of May and September. The Yellowstone Sand Verbena
Abronia ammophila
Abronia ammophila, the Yellowstone sand verbena, is a plant unique to Yellowstone National Park lakeshores and is endemic to the park....

 is a rare flowering plant found only in Yellowstone. It is closely related to species usually found in much warmer climates, making the sand verbena an enigma. The estimated 8,000 examples of this rare flowering plant all make their home in the sandy soils on the shores of Yellowstone Lake, well above the waterline.

In Yellowstone's hot waters, bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 form mats of bizarre shapes consisting of trillions of individuals. These bacteria are some of the most primitive life forms on earth. Flies and other arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...

s live on the mats, even in the middle of the bitterly cold winters. Initially, scientists thought that microbes there gained sustenance only from sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

. In 2005, researchers from the University of Colorado at Boulder
University of Colorado at Boulder
The University of Colorado Boulder is a public research university located in Boulder, Colorado...

 discovered that the sustenance for at least some of the diverse hyperthermophilic species is molecular hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

.

Thermus aquaticus
Thermus aquaticus
Thermus aquaticus is a species of bacterium that can tolerate high temperatures, one of several thermophilic bacteria that belong to the Deinococcus-Thermus group...

is a bacterium
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 found in the Yellowstone hot springs that produces an important enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that is easily replicated in the lab and is useful in replicating DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 as part of the polymerase chain reaction
Polymerase chain reaction
The polymerase chain reaction is a scientific technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence....

 (PCR) process. The retrieval of these bacteria can be achieved with no impact to the ecosystem. Other bacteria in the Yellowstone hot springs may also prove useful to scientists who are searching for cures for various diseases.

Non-native plants sometimes threaten native species by using up nutrient resources. Though exotic species are most commonly found in areas with the greatest human visitation, such as near roads and at major tourist areas, they have also spread into the backcountry. Generally, most exotic species are controlled by pulling the plants out of the soil or by spraying, both of which are time consuming and expensive.

Fauna

Yellowstone is widely considered to be the finest megafauna
Megafauna
In terrestrial zoology, megafauna are "giant", "very large" or "large" animals. The most common thresholds used are or...

 wildlife habitat in the lower 48 states
Contiguous United States
The contiguous United States are the 48 U.S. states on the continent of North America that are south of Canada and north of Mexico, plus the District of Columbia....

. There are almost 60 species of mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s in the park, including the gray wolf
Gray Wolf
The gray wolf , also known as the wolf, is the largest extant wild member of the Canidae family...

, the threatened
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...

 lynx
Lynx
A lynx is any of the four Lynx genus species of medium-sized wildcats. The name "lynx" originated in Middle English via Latin from Greek word "λύγξ", derived from the Indo-European root "*leuk-", meaning "light, brightness", in reference to the luminescence of its reflective eyes...

, and grizzly bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...

s. Other large mammals include the bison
American Bison
The American bison , also commonly known as the American buffalo, is a North American species of bison that once roamed the grasslands of North America in massive herds...

 (buffalo), black bear
American black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...

, elk
Elk
The Elk is the large deer, also called Cervus canadensis or wapiti, of North America and eastern Asia.Elk may also refer to:Other antlered mammals:...

, moose
Moose
The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...

, mule deer
Mule Deer
The mule deer is a deer indigenous to western North America. The Mule Deer gets its name from its large mule-like ears. There are believed to be several subspecies, including the black-tailed deer...

, white-tailed deer
White-tailed Deer
The white-tailed deer , also known as the Virginia deer or simply as the whitetail, is a medium-sized deer native to the United States , Canada, Mexico, Central America, and South America as far south as Peru...

, mountain goat
Mountain goat
The Mountain Goat , also known as the Rocky Mountain Goat, is a large-hoofed mammal found only in North America. Despite its vernacular name, it is not a member of Capra, the genus of true goats...

, pronghorn
Pronghorn
The pronghorn is a species of artiodactyl mammal endemic to interior western and central North America. Though not an antelope, it is often known colloquially in North America as the prong buck, pronghorn antelope, or simply antelope, as it closely resembles the true antelopes of the Old World and...

, bighorn sheep
Bighorn Sheep
The bighorn sheep is a species of sheep in North America named for its large horns. These horns can weigh up to , while the sheep themselves weigh up to . Recent genetic testing indicates that there are three distinct subspecies of Ovis canadensis, one of which is endangered: Ovis canadensis sierrae...

 and mountain lion.

The Yellowstone Park Bison Herd
Yellowstone Park Bison Herd
The Yellowstone Park bison herd in Yellowstone National Park is probably the oldest and largest public bison herd in the United States of America. Yellowstone is known for its geothermal activity and large mammals, especially Elk, Wolves, American Bison, Bears, Pronghorn Antelope, Moose and Bighorn...

 is the largest public herd of American Bison
American Bison
The American bison , also commonly known as the American buffalo, is a North American species of bison that once roamed the grasslands of North America in massive herds...

 in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. The relatively large bison populations are a concern for ranchers, who fear that the species can transmit bovine diseases to their domesticated cousins. In fact, about half of Yellowstone's bison have been exposed to brucellosis
Brucellosis
Brucellosis, also called Bang's disease, Crimean fever, Gibraltar fever, Malta fever, Maltese fever, Mediterranean fever, rock fever, or undulant fever, is a highly contagious zoonosis caused by ingestion of unsterilized milk or meat from infected animals or close contact with their secretions...

, a bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

l disease that came to North America with European cattle that may cause cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...

 to miscarry
Miscarriage
Miscarriage or spontaneous abortion is the spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving independently, generally defined in humans at prior to 20 weeks of gestation...

. The disease has little effect on park bison, and no reported case of transmission from wild bison to domestic livestock has been filed. However, the Animal and Plant Health Inspection Service
Animal and Plant Health Inspection Service
Animal and Plant Health Inspection Service is an agency of the United States Department of Agriculture responsible for protecting animal health, animal welfare, and plant health. APHIS is the lead agency for collaboration with other agencies to protect U.S. agriculture from invasive pests and...

 (APHIS) has stated that Bison are the "likely source" of the spread of the disease in cattle in Wyoming and North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....

. Elk also carry the disease and are believed to have transmitted the infection to horses and cattle. Bison once numbered between 30 and 60 million individuals throughout North America, and Yellowstone remains one of their last strongholds. Their populations had increased from less than 50 in the park in 1902 to 4,000 by 2003. The Yellowstone Park Bison Herd
Yellowstone Park Bison Herd
The Yellowstone Park bison herd in Yellowstone National Park is probably the oldest and largest public bison herd in the United States of America. Yellowstone is known for its geothermal activity and large mammals, especially Elk, Wolves, American Bison, Bears, Pronghorn Antelope, Moose and Bighorn...

 reached a peak in 2005 with 4,900 animals. Despite a summer estimated population of 4,700 in 2007, the number dropped to 3,000 in 2008 after a harsh winter and controversial brucellosis management sending hundreds to slaughter. The Yellowstone Park Bison Herd
Yellowstone Park Bison Herd
The Yellowstone Park bison herd in Yellowstone National Park is probably the oldest and largest public bison herd in the United States of America. Yellowstone is known for its geothermal activity and large mammals, especially Elk, Wolves, American Bison, Bears, Pronghorn Antelope, Moose and Bighorn...

 is believed to be one of only four free roaming and genetically pure herds on public lands in North America. The other three herds are the Henry Mountains Bison Herd
Henry Mountains Bison Herd
The Henry Mountains Bison Herd, numbering 250 to 400 bison, is believed to be one of only four free roaming and genetically pure herds on public lands in North America...

 of Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

, at Wind Cave National Park
Wind Cave National Park
Wind Cave National Park is a United States national park north of the town of Hot Springs in western South Dakota. Established in 1903 by President Theodore Roosevelt, it was the seventh U.S. National Park and the first cave to be designated a national park anywhere in the world. The cave is...

 in South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...

 and on Elk Island in Alberta, Canada.

To combat the perceived threat, national park personnel regularly harass bison herds back into the park when they venture outside of the area's borders. During the winter of 1996–97, the bison herd was so large that 1,079 bison that had exited the park were shot or sent to slaughter. Animal rights
Animal rights
Animal rights, also known as animal liberation, is the idea that the most basic interests of non-human animals should be afforded the same consideration as the similar interests of human beings...

 activists argue that this is a cruel practice and that the possibility for disease transmission is not as great as some ranchers maintain. Ecologists point out that the bison are merely traveling to seasonal grazing areas that lie within the Greater Yellowstone Ecosystem that have been converted to cattle grazing, some of which are within National Forests and are leased to private ranchers. APHIS has stated that with vaccinations and other means, brucellosis can be eliminated from the bison and elk herds throughout Yellowstone.

Starting in 1914, in an effort to protect elk populations, the U.S. Congress appropriated funds to be used for the purposes of "destroying wolves, prairie dogs, and other animals injurious to agriculture and animal husbandry" on public lands. Park Service hunters carried out these orders, and by 1926 they had killed 136 wolves, and wolves were virtually eliminated from Yellowstone. Further exterminations continued until the National Park Service ended the practice in 1935. With the passing of the Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...

 in 1973, the wolf was one of the first mammal species listed. After the wolves were extirpated from Yellowstone, the coyote
Coyote
The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...

 then became the park's top canine predator. However, the coyote is not able to bring down large animals, and the result of this lack of a top predator on these populations was a marked increase in lame and sick megafauna.

By the 1990s, the Federal government had reversed its views on wolves. In a controversial decision by the U.S. Fish and Wildlife Service (which oversees threatened and endangered species), Mackenzie Valley wolves
Mackenzie Valley Wolf
The Mackenzie Valley Wolf also known as the Canadian Timber Wolf is perhaps the largest subspecies of Gray Wolf in North America. Its range includes parts of the western United States, much of western Canada, and Alaska, including Unimak Island in the Aleutians, and was introduced into Yellowstone...

, imported from Canada, were reintroduced into the park. Reintroduction efforts have been successful with populations remaining relatively stable. A survey conducted in 2005 reported that there were 13 wolf packs, totaling 118 individuals in Yellowstone and 326 in the entire ecosystem. These park figures were lower than those reported in 2004 but may be attributable to wolf migration to other nearby areas as suggested by the substantial increase in the Montana population during that interval. Almost all the wolves documented were descended from the 66 wolves reintroduced in 1995–96. The recovery of populations throughout the states of Wyoming, Montana and Idaho has been so successful that on February 27, 2008 the U.S. Fish and Wildlife Service removed the Northern Rocky Mountain wolf population from the endangered species list.

An estimated 600 grizzly bears live in the Greater Yellowstone Ecosystem, with more than half of the population living within Yellowstone. The grizzly is currently listed as a threatened species, however the U.S. Fish and Wildlife Service has announced that they intend to take it off the endangered species list for the Yellowstone region but will likely keep it listed in areas where it has not yet recovered fully. Opponents of delisting the grizzly are concerned that states might once again allow hunting and that better conservation measures need to be implemented to ensure a sustainable population.

Population figures for elk are in excess of 30,000—the largest population of any large mammal species in Yellowstone. The northern herd has decreased enormously since the mid-1990s; this has been attributed to wolf predation and causal effects such as elk using more forested regions to evade predation, consequently making it harder for researchers to accurately count them. The northern herd migrates west into southwestern Montana in the winter. The southern herd migrates southward, and the majority of these elk winter on the National Elk Refuge
National Elk Refuge
The National Elk Refuge is located in the U.S. state of Wyoming and was created in 1912 to protect habitat and provide sanctuary for the largest elk herd on Earth. The refuge borders the town of Jackson, Wyoming on the northeast while Bridger-Teton National Forest is to the east and Grand Teton...

, immediately southeast of Grand Teton National Park. The southern herd migration is the largest mammalian migration remaining in the U.S. outside of Alaska.

In 2003, the tracks of one female lynx and her cub were spotted and followed for over 2 miles (3.2 km). Fecal material and other evidence obtained were tested and confirmed to be those of a lynx. No visual confirmation was made, however. Lynx have not been seen in Yellowstone since 1998, though DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 taken from hair samples obtained in 2001 confirmed that lynx were at least transient to the park. Other less commonly seen mammals include the mountain lion and wolverine
Wolverine
The wolverine, pronounced , Gulo gulo , also referred to as glutton, carcajou, skunk bear, or quickhatch, is the largest land-dwelling species of the family Mustelidae . It is a stocky and muscular carnivore, more closely resembling a small bear than other mustelids...

. The mountain lion has an estimated population of only 25 individuals parkwide. The wolverine is another rare park mammal, and accurate population figures for this species are not known. These uncommon and rare mammals provide insight into the health of protected lands such as Yellowstone and help managers make determinations as to how best to preserve habitats.

Eighteen species of fish live in Yellowstone, including the core range of the Yellowstone cutthroat trout
Yellowstone cutthroat trout
The Yellowstone cutthroat trout is a subspecies of the cutthroat trout and is a freshwater fish in the salmon family of the order Salmoniformes. Native only to a few U.S...

—a fish highly sought by anglers
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....

. The Yellowstone cutthroat trout has faced several threats since the 1980s, including the suspected illegal introduction into Yellowstone Lake of lake trout
Lake trout
Lake trout is a freshwater char living mainly in lakes in northern North America. Other names for it include mackinaw, lake char , touladi, togue, and grey trout. In Lake Superior, they can also be variously known as siscowet, paperbellies and leans...

, an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 which consume the smaller cutthroat trout. Although lake trout were established in Shoshone
Shoshone Lake
Shoshone Lake is a backcountry lake with the area of elevated at in the southwest section of Yellowstone National Park, Wyoming, US. It lies at the headwaters of the Lewis River a tributary of the Snake River. The U.S...

 and Lewis
Lewis Lake (Wyoming)
Lewis Lake is located in the U. S. state of Wyoming in the southern part of Yellowstone National Park, about southeast of Shoshone Lake, and approximately southwest of Yellowstone Lake. Lewis Lake and Shoshone Lake are both located a few miles northeast of the Pitchstone Plateau.The Lewis River...

 lakes in the Snake River drainage from U.S. Government stocking operations in 1890, it was never officially introduced into the Yellowstone River drainage. The cutthroat trout has also faced an ongoing drought, as well as the accidental introduction of a parasite—whirling disease
Myxobolus cerebralis
Myxobolus cerebralis is a myxosporean parasite of salmonids that causes whirling disease in farmed salmon and trout and also in wild fish populations...

—which causes a terminal nervous system disease in younger fish. Since 2001, all native sport fish species caught in Yellowstone waterways are subject to a catch and release law. Yellowstone is also home to six species of reptiles, such as the painted turtle
Painted Turtle
The painted turtle is the most widespread native turtle of North America. It lives in slow-moving fresh waters, from southern Canada to Louisiana and northern Mexico, and from the Atlantic to the Pacific. The turtle is the only species of the genus Chrysemys, which is part of the pond turtle...

 and Prairie rattlesnake
Crotalus viridis
Crotalus viridis is a venomous pitviper species native to the western United States, southwestern Canada, and northern Mexico. Currently, nine subspecies are recognized, including the nominate subspecies described here.-Description:...

, and four species of amphibians, including the Boreal Chorus Frog
Boreal Chorus Frog
The Boreal Chorus Frog, is a species of chorus frog native to Canada from the west of Lake Superior to western Alberta and north to the Northwest Territories...

.

311 species of birds have been reported, almost half of which nest in Yellowstone. As of 1999, twenty-six pairs of nesting bald eagles have been documented. Extremely rare sightings of whooping crane
Whooping Crane
The whooping crane , the tallest North American bird, is an endangered crane species named for its whooping sound. Along with the Sandhill Crane, it is one of only two crane species found in North America. The whooping crane's lifespan is estimated to be 22 to 24 years in the wild...

s have been recorded, however only three examples of this species are known to live in the Rocky Mountains, out of 385 known worldwide. Other birds, considered to be species of special concern because of their rarity in Yellowstone, include the common loon, harlequin duck
Harlequin Duck
The Harlequin Duck is a small sea duck. It takes its name from Arlecchino, Harlequin in French, a colourfully dressed character in Commedia dell'arte. The species name comes from the Latin word "histrio", "actor". In North America it is also known as Lords and ladies...

, osprey
Osprey
The Osprey , sometimes known as the sea hawk or fish eagle, is a diurnal, fish-eating bird of prey. It is a large raptor, reaching more than in length and across the wings...

, peregrine falcon
Peregrine Falcon
The Peregrine Falcon , also known as the Peregrine, and historically as the Duck Hawk in North America, is a widespread bird of prey in the family Falconidae. A large, crow-sized falcon, it has a blue-gray back, barred white underparts, and a black head and "moustache"...

 and the trumpeter swan
Trumpeter Swan
The Trumpeter Swan, Cygnus buccinator, is the largest native North American bird, if measured in terms of weight and length, and is the largest living waterfowl species on earth. It is the North American counterpart of the European Whooper Swan.-Description:Males typically measure from and weigh...

.

Forest fires

Wildfire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...

 is a natural part of most ecosystems, and plants found in Yellowstone have adapted in a variety of ways. Douglas-fir
Rocky Mountain Douglas-fir
The Rocky Mountain Douglas-fir, Pseudotsuga menziesii subsp. glauca, is an evergreen conifer native to the interior mountainous regions of western North America, from central British Columbia and southwest Alberta in Canada southward through the United States to the far north of Mexico...

 has a thick bark which protects the inner section of the tree from most fires. Lodgepole Pine
Lodgepole Pine
Lodgepole Pine, Pinus contorta, also known as Shore Pine, is a common tree in western North America. Like all pines, it is evergreen.-Subspecies:...

s —the most common tree species in the park— generally have cones that are only opened by the heat of fire. Their seeds are held in place by a tough resin, and fire assists in melting the resin, allowing the seeds to disperse. Fire clears out dead and down wood, providing fewer obstacles for lodgepole pines to flourish. Subalpine Fir
Subalpine Fir
The Subalpine Fir or Rocky Mountain Fir is a western North American fir, native to the mountains of Yukon, British Columbia and western Alberta in Canada; southeastern Alaska, Washington, Oregon, Idaho, western Montana, Wyoming, Utah, Colorado, New Mexico, Arizona, northeastern Nevada, and the...

, Engelmann Spruce
Engelmann Spruce
Picea engelmannii is a species of spruce native to western North America, from central British Columbia and southwest Alberta, southwest to northern California and southeast to Arizona and New Mexico; there are also two isolated populations in northern Mexico...

, Whitebark Pine
Whitebark Pine
Pinus albicaulis, known commonly as Whitebark Pine, Pitch Pine, Scrub Pine, and Creeping Pine occurs in the mountains of the Western United States and Canada, specifically the subalpine areas of the Sierra Nevada, the Cascade Range, the Pacific Coast Ranges, and the northern Rocky Mountains –...

 and other species tend to grow in colder and moister areas, where fire is less likely to occur. Aspen
Populus tremuloides
Populus tremuloides is a deciduous tree native to cooler areas of North America, commonly called quaking aspen, trembling aspen, American aspen, and Quakies,. The trees have tall trunks, up to 25 metres, with smooth pale bark, scarred with black. The glossy green leaves, dull beneath, become golden...

 trees sprout new growth from their roots, and even if a severe fire kills the tree above ground, the roots often survive unharmed because they are insulated from the heat by soil. The National Park Service estimates that in natural conditions, grasslands in Yellowstone burned an average of every 20 to 25 years, while forests in the park would experience fire about every 300 years.

About thirty-five natural forest fires are ignited each year by lightning
Lightning
Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...

, while another six to ten are started by people— in most cases by accident. Yellowstone National Park has three fire lookout towers
Fire lookout
A fire lookout is a person assigned the duty to look for fire from atop a building known as a fire lookout tower. These towers are used in remote areas, normally on mountain tops with high elevation and a good view of the surrounding terrain, to spot smoke caused by a wildfire.Once a possible fire...

, each staffed by trained fire fighters. The easiest one to reach is atop Mount Washburn, though it is closed to the public. The park also monitors fire from the air and relies on visitor reports of smoke and/or flames. Fire towers are staffed almost continuously from late June to mid-September— the primary fire season. Fires burn with the greatest intensity in the late afternoon and evening. Few fires burn more than 100 acres (40.5 ha), and the vast majority of fires reach only a little over an acre (0.5 ha) before they burn themselves out. Fire management focuses on monitoring dead and down wood quantities, soil and tree moisture, and the weather, to determine those areas most vulnerable to fire should one ignite. Current policy is to suppress all human caused fires and to evaluate natural fires, examining the benefit or detriment they may pose on the ecosystem. If a fire is considered to be an immediate threat to people and structures, or will burn out of control, then fire suppression is performed.

In an effort to minimize the chances of out of control fires and threats to people and structures, park employees do more than just monitor the potential for fire. Controlled burn
Controlled burn
Controlled or prescribed burning, also known as hazard reduction burning or Swailing is a technique sometimes used in forest management, farming, prairie restoration or greenhouse gas abatement. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for...

s are prescribed fires which are deliberately started to remove dead timber under conditions which allow fire fighters an opportunity to carefully control where and how much wood is consumed. Natural fires are sometimes considered prescribed fires if they are left to burn. In Yellowstone, unlike some other parks, there have been very few fires deliberately started by employees as prescribed burns. However, over the last 30 years, over 300 natural fires have been allowed to burn naturally. In addition, fire fighters remove dead and down wood and other hazards from areas where they will be a potential fire threat to lives and property, reducing the chances of fire danger in these areas. Fire monitors also regulate fire through educational services to the public and have been known to temporarily ban campfires from campgrounds during periods of high fire danger.
The common notion in early United States land management policies was that all forest fires were bad. Fire was seen as a purely destructive force and there was little understanding that it was an integral part of the ecosystem. Consequently, until the 1970s, when a better understanding of wildfire was developed, all fires were suppressed. This led to an increase in dead and dying forests, which would later provide the fuel load for fires that would be much harder, and in some cases, impossible to control. Fire Management Plans were implemented, detailing that natural fires should be allowed to burn if they posed no immediate threat to lives and property.

1988 started with a wet spring season although by summer, drought began moving in throughout the northern Rockies, creating the driest year on record to that point, courtesy of the droughts of 1988 and 1989. Grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...

es and plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s which grew well in the early summer from the abundant spring moisture produced plenty of grass, which soon turned to dry tinder. The National Park Service began firefighting efforts to keep the fires under control, but the extreme drought made suppression difficult. Between July 15 and July 21, 1988, fires quickly spread from 8500 acre (3,439.8 ha; 13.3 sq mi) throughout the entire Yellowstone region, which included areas outside the park, to 99000 acre (40,063.9 ha; 154.7 sq mi) on the park land alone. By the end of the month, the fires were out of control. Large fires burned together, and on August 20, 1988, the single worst day of the fires, more than 150000 acre (60,702.9 ha; 234.4 sq mi) were consumed. Seven large fires were responsible for 95% of the 793000 acre (320,916 ha; 1,239.1 sq mi) that were burned over the next couple of months. A total of 25,000 firefighters and U.S. military forces participated in the suppression efforts, at a cost of 120 million dollars. By the time winter brought snow that helped extinguish the last flames, the fires had destroyed 67 structures and caused several million dollars in damage. Though no civilian lives were lost, two personnel associated with the firefighting efforts were killed.

Contrary to media reports and speculation at the time, the fires killed very few park animals— surveys indicated that only about 345 elk (of an estimated 40,000–50,000), 36 deer, 12 moose, 6 black bears, and 9 bison had perished. Changes in fire management policies were implemented by land management agencies throughout the U.S., based on knowledge gained from the 1988 fires and the evaluation of scientists and experts from various fields. By 1992, Yellowstone had adopted a new fire management plan which observed stricter guidelines for the management of natural fires.

Climate

Yellowstone climate is greatly influenced by altitude, with lower elevations generally found to be warmer year round. The record high temperature was 99 °F (37.2 °C) in 2002, while the coldest temperature recorded is −66 °F in 1933. During the summer months of June through early September, daytime highs are normally in the 70 to 80 °F (21.1 to 26.7 C) range, while nighttime lows can go to below freezing (0 °C)—especially at higher altitudes. Summer afternoons are frequently accompanied by thunderstorm
Thunderstorm
A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...

s. Spring and fall temperatures range between 30 and 60 °F (-1.1 and 15.6 C) with cold nights in the teens to single digits (−5 to −20 °C). Winter in Yellowstone is very cold with high temperatures usually between zero to 20 °F (−20 to −5 °C) and nighttime temperatures below zero °F (−20 °C) for most of the winter.

Precipitation in Yellowstone is highly variable and ranges from 15 inches (381 mm) annually near Mammoth Hot Springs, to 80 inches (2,032 mm) in the southwestern sections of the park. The precipitation of Yellowstone is greatly influenced by the moisture channel formed by the Snake River Plain
Snake River Plain
The Snake River Plain is a geologic feature located primarily within the state of Idaho in the United States of America. It stretches about westward from northwest of the state of Wyoming to the Idaho-Oregon border. The plain is a wide flat bow-shaped depression, and covers about a quarter of Idaho...

 to the west that was, in turn, formed by Yellowstone itself. Snow is possible in any month of the year, with averages of 150 inches (3,810 mm) annually around Yellowstone Lake, to twice that amount at higher elevations.

Tornado
Tornado
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone, although the word cyclone is used in meteorology in a wider...

es in Yellowstone are rare; however, on July 21, 1987, the most powerful tornado recorded in Wyoming touched down in the Teton Wilderness
Teton Wilderness
Teton Wilderness is located in Wyoming, United States. Created in 1964, the Teton Wilderness is located within Bridger-Teton National Forest and consists of 585,238 acres . The wilderness is bordered on the north by Yellowstone National Park and to the west by Grand Teton National Park and the John...

 of Bridger-Teton National Forest
Bridger-Teton National Forest
Bridger-Teton National Forest is located in western Wyoming, United States. The forest consists of , making it the second largest National Forest outside of Alaska. The forest stretches from Yellowstone National Park, along the eastern boundary of Grand Teton National Park and from there rides...

 and hit Yellowstone National Park. Called the Teton–Yellowstone tornado
Teton–Yellowstone tornado
The Teton–Yellowstone tornado was a rare high-altitude tornado which occurred on July 21, 1987 in the U.S. State of Wyoming. Rated at F4 on the fujita scale, it was the strongest tornado ever recorded in the state. The tornado cut through a long, wide swath of the Teton Wilderness and...

, it was classified as an F4
Fujita scale
The Fujita scale , or Fujita-Pearson scale, is a scale for rating tornado intensity, based primarily on the damage tornadoes inflict on human-built structures and vegetation...

, with wind speeds estimated at between 207 and 260 mph (333.1 and 418.4 km/h). The tornado left a path of destruction 1 to 2 mi (1.6 to 3.2 km) wide, and 24 miles (38.6 km) long, and leveled 15000 acre (6,070.3 ha; 23.4 sq mi) of mature pine forest.

Recreation

Yellowstone is one of the most popular national parks in the United States. Since the mid-1960s, at least 2 million tourists have visited the park almost every year. In 2010, a record number of visitors came to the park in July: 975,000. July is the busiest month for Yellowstone National Park. At peak summer levels, 3,700 employees work for Yellowstone National Park concessionaires. Concessionaires manage nine hotels and lodges, with a total of 2,238 hotel rooms and cabins available. They also oversee gas stations, stores and most of the campgrounds. Another 800 employees work either permanently or seasonally for the National Park Service.

Park service roads lead to major features; however, road reconstruction has produced temporary road closures. Yellowstone is in the midst of a long term road reconstruction effort, which is hampered by a short repair season. In the winter, all roads aside from the one which enters from Gardiner
Gardiner, Montana
Gardiner is a census-designated place in Park County, Montana, United States, along the 45th parallel. The population was 851 at the 2000 census....

, Montana, and extends to Cooke City, Montana, are closed to wheeled vehicles. Park roads are closed to wheeled vehicles from early November to mid April, but some park roads remain closed until mid-May. The park has 310 miles (498.9 km) of paved roads which can be accessed from 5 different entrances. There is no public transportation available inside the park, but several tour companies can be contacted for guided motorized transport. In the winter, concessionaires operate guided snowmobile
Snowmobile
A snowmobile, also known in some places as a snowmachine, or sled,is a land vehicle for winter travel on snow. Designed to be operated on snow and ice, they require no road or trail. Design variations enable some machines to operate in deep snow or forests; most are used on open terrain, including...

 and snow coach
Snow coach
A snow coach is a specialized passenger transport vehicle, designed to operate over snow or ice, similar to alarge, multi-passenger snowcat that is equipped with bus style seating. These vehicles may have multiple sets of very large low pressure tires or they may have tracks...

 tours, though their numbers and access are based on quotas established by the National Park Service. Facilities in the Old Faithful, Canyon and Mammoth Hot Springs areas of the park are very busy during the summer months. Traffic jams created by road construction or by people observing wildlife can result in long delays.

The National Park Service maintains 9 visitor centers and museums and is responsible for maintenance of historical structures and many of the other 2,000 buildings. These structures include National Historical Landmarks such as the Old Faithful Inn
Old Faithful Inn
-Sources:*Barringer, Mark Daniel. Selling Yellowstone: Capitalism and the Construction of Nature, Lawrence, Kansas: University Press of Kansas, 2002. ISBN 978-070061167-3...

 built in 1903–04 and the entire Fort Yellowstone - Mammoth Hot Springs Historic District
Fort Yellowstone
-See also:* Grand Loop Road Historic District* Lake Fish Hatchery Historic District* Mammoth Hot Springs Historic District* North Entrance Road Historic District* Roosevelt Lodge Historic District* Old Faithful Historic District* US Post Office-Yellowstone Main...

. An historical and educational tour is available at Fort Yellowstone which details the history of the National Park Service and the development of the park. Campfire programs, guided walks and other interpretive presentations are available at numerous locations in the summer, and on a limited basis during other seasons.

Camping
Camping
Camping is an outdoor recreational activity. The participants leave urban areas, their home region, or civilization and enjoy nature while spending one or several nights outdoors, usually at a campsite. Camping may involve the use of a tent, caravan, motorhome, cabin, a primitive structure, or no...

 is available at a dozen campgrounds with more than 2,000 campsites. Camping is also available in surrounding National Forests, as well as in Grand Teton National Park to the south. Backcountry
Backcountry
A backcountry area in general terms is a geographical region that is:* isolated* remote* undeveloped* difficult to accessThe term may apply to various regions that are reasonably close to urban areas but are:* not immediately accessible by car...

 campsites are accessible only by foot or by horseback and require a permit. There are 1100 miles (1,770.3 km) of hiking
Hiking
Hiking is an outdoor activity which consists of walking in natural environments, often in mountainous or other scenic terrain. People often hike on hiking trails. It is such a popular activity that there are numerous hiking organizations worldwide. The health benefits of different types of hiking...

 trails available. The park is not considered to be a good destination for mountaineering
Mountaineering
Mountaineering or mountain climbing is the sport, hobby or profession of hiking, skiing, and climbing mountains. While mountaineering began as attempts to reach the highest point of unclimbed mountains it has branched into specialisations that address different aspects of the mountain and consists...

 because of the instability of volcanic rock which predominates. Visitors with pets are required to keep them on a leash at all times and are limited to areas near roadways and in "frontcountry" zones such as drive in campgrounds. Around thermal features, wooden and paved trails have been constructed to ensure visitor safety, and most of these areas are handicapped accessible. The National Park Service maintains a year round clinic at Mammoth Hot Springs and provides emergency services throughout the year.

Hunting
Hunting
Hunting is the practice of pursuing any living thing, usually wildlife, for food, recreation, or trade. In present-day use, the term refers to lawful hunting, as distinguished from poaching, which is the killing, trapping or capture of the hunted species contrary to applicable law...

 is not permitted, though it is allowed in the surrounding national forests during season. Fishing
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....

 is a popular activity, and a Yellowstone Park fishing license is required to fish in park waters. Many park waters are fly fishing
Fly fishing
Fly fishing is an angling method in which an artificial 'fly' is used to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. Casting a nearly weightless fly or 'lure' requires casting techniques significantly different from other forms of casting...

 only and all native fish species are catch and release
Catch and release
Catch and release is a practice within recreational fishing intended as a technique of conservation. After capture, the fish are unhooked and returned to the water before experiencing serious exhaustion or injury...

 only. Boating is prohibited on rivers and creeks except for a 5 miles (8 km) stretch of the Lewis River between Lewis and Shoshone Lake
Shoshone Lake
Shoshone Lake is a backcountry lake with the area of elevated at in the southwest section of Yellowstone National Park, Wyoming, US. It lies at the headwaters of the Lewis River a tributary of the Snake River. The U.S...

, and it is open to non-motorized use only. Yellowstone Lake has a marina, and the lake is the most popular boating destination.

In the early history of the park, visitors were allowed, and sometimes even encouraged, to feed the bears. The bears had learned to beg for food, and visitors welcomed the chance to get their pictures taken with them. This led to numerous injuries to humans each year. In 1970, park officials changed their policy and started a vigorous program to educate the public on the dangers of close contact with bears, and to try to eliminate opportunities for bears to find food in campgrounds and trash collection areas. Although it has become more difficult to observe them in recent years, the number of human injuries and deaths has taken a significant drop and visitors are in less danger.

Other protected lands in the region include Caribou-Targhee
Caribou-Targhee National Forest
Caribou-Targhee National Forest is located in the states of Idaho and Wyoming, with a small section in Utah in the United States. The forest is broken into several separate sections and extends over . To the east the forest borders Yellowstone National Park, Grand Teton National Park and...

, Gallatin
Gallatin National Forest
Founded in 1899, Gallatin National Forest is located in south central Montana, United States. The forest comprises 2.1 million acres and has portions of both the Absaroka-Beartooth and Lee Metcalf Wilderness areas within its boundaries...

, Custer
Custer National Forest
Custer National Forest is located primarily in the southern part of the U.S. state of Montana but also has separate sections in northwestern South Dakota. With a total area of 1,278,279 acres , the forest comprises over 10 separate sections...

, Shoshone
Shoshone National Forest
Shoshone National Forest is the first federally protected National Forest in the United States and covers nearly 2.5 million acres in the state of Wyoming. Originally a part of the Yellowstone Timberland Reserve, the forest was created by an act of Congress and signed into law by U.S....

 and Bridger-Teton National Forests. The National Park Service's John D. Rockefeller, Jr. Memorial Parkway
John D. Rockefeller, Jr. Memorial Parkway
John D. Rockefeller, Jr. Memorial Parkway is a scenic road that connects Grand Teton National Park and Yellowstone National Park in Wyoming, United States. It is federally owned and managed by the National Park Service. It is named in remembrance of John D...

 is to the south and leads to Grand Teton National Park. The famed Beartooth Highway
Beartooth Highway
The Beartooth Highway is an All-American Road that has been called "the most beautiful drive in America," by late CBS correspondent Charles Kuralt...

 provides access from the northeast and has spectacular high altitude scenery. Nearby communities include West Yellowstone
West Yellowstone, Montana
West Yellowstone is a town in Gallatin County, Montana, adjacent to Yellowstone National Park. The population was 1,177 at the 2000 census. The town is served by Yellowstone Airport...

, Montana; Cody
Cody, Wyoming
Cody is a city in Park County, Wyoming, United States. It is named after William Frederick Cody, primarily known as Buffalo Bill, from William Cody's part in the creation of the original town. The population was 9,520 at the 2010 census...

, Wyoming; Red Lodge
Red Lodge, Montana
Red Lodge is a city in and the county seat of Carbon County, Montana, United States. It is part of the Billings, Montana Metropolitan Statistical Area...

, Montana; Ashton
Ashton, Idaho
Ashton is a city in Fremont County, Idaho, United States. It is part of the Rexburg, Idaho Micropolitan Statistical Area. The population was 1,129 at the 2000 census. The district is noted for seed potato production and bills itself as the world's largest seed potato growing area.-Geography and...

, Idaho; and Gardiner
Gardiner, Montana
Gardiner is a census-designated place in Park County, Montana, United States, along the 45th parallel. The population was 851 at the 2000 census....

, Montana. The closest air transport is available by way of Bozeman
Bozeman, Montana
Bozeman is a city in and the county seat of Gallatin County, Montana, United States, in the southwestern part of the state. The 2010 census put Bozeman's population at 37,280 making it the fourth largest city in the state. It is the principal city of the Bozeman micropolitan area, which consists...

, Montana; Billings
Billings, Montana
Billings is the largest city in the U.S. state of Montana, and is the principal city of the Billings Metropolitan Area, the largest metropolitan area in over...

, Montana; Jackson
Jackson, Wyoming
Jackson is a town located in the Jackson Hole valley of Teton County, Wyoming, United States. The population was 8,647 at the 2000 census. It is the county seat of Teton County....

; Cody
Cody, Wyoming
Cody is a city in Park County, Wyoming, United States. It is named after William Frederick Cody, primarily known as Buffalo Bill, from William Cody's part in the creation of the original town. The population was 9,520 at the 2010 census...

, Wyoming or Idaho Falls
Idaho Falls, Idaho
Idaho Falls is a city in and the county seat of Bonneville County, Idaho, United States, and the largest city in Eastern Idaho. As of the 2010 census, the population of Idaho Falls was 56,813, with a metro population of 130,374....

, Idaho. Salt Lake City, 320 miles (515 km) to the south, is the closest large metropolitan area.

Legal jurisdiction

The entire park is within the jurisdiction of the United States District Court for the District of Wyoming
United States District Court for the District of Wyoming
The United States District Court for the District of Wyoming is the Federal district court whose jurisdiction comprises the state of Wyoming and those portions of Yellowstone National Park situated in Montana and Idaho...

, causing it to be the only federal court district that includes portions of more than one state (Idaho, Montana and Wyoming). At least one legal scholar has written, and a defendant argued, that this situation creates a legal loophole
Loophole
A loophole is a weakness that allows a system to be circumvented.Loophole may also refer to:*Arrowslit, a slit in a castle wall*Loophole , a short science fiction story by Arthur C...

 by which individuals accused of committing crimes in the Montana and Idaho portions of the park cannot be legally tried.

See also


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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