The
Blue Mountains are a
mountain rangeA 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...
in the western
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
, located largely in northeastern
OregonOregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
and stretching into southeastern Washington. The range, situated in the
Pacific NorthwestThe Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
, has an area of 4060 square miles (10,515.4 km²), stretching east and southeast of
PendletonPendleton is a city in Umatilla County, Oregon, United States. Pendleton was named in 1868 by the county commissioners for George H. Pendleton, Democratic candidate for Vice-President in the 1864 presidential campaign. The population was 16,612 at the 2010 census...
, Oregon, to the
Snake RiverThe 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...
along the Oregon-
IdahoIdaho 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....
border.
GeologicallyGeology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
, the range is a part of the larger rugged
Columbia River PlateauThe Columbia Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Columbia River...
, located in the dry area of Oregon east of the
Cascade RangeThe Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...
. The highest peaks in the range include the Elkhorn Mountains at 9108 feet (2,776.1 m), Strawberry Mountain at 9038 feet (2,754.8 m), and
Mount IrelandMount Ireland is a mountain in Grant County of the U.S. state of Oregon. It is about east-northeast of Granite, Oregon. It is the second highest peak in the Blue Mountains at after Strawberry Mountain, and Oregon's 71st highest peak...
at 8304 feet (2,531.1 m). The nearby
Wallowa MountainsThe Wallowa Mountains are a mountain range located in the Columbia Plateau of northeastern Oregon in the United States. The range runs approximately 40 mi northwest to southeast in southwestern Wallowa County between the Blue Mountains to the west and the Snake River to the east. The range is...
, east of the main range near the Snake River, are sometimes included as a subrange of the Blue Mountains.
In the middle 19th century, the Blue Mountains were a formidable obstacle on the
Oregon TrailThe Oregon Trail is a historic east-west wagon route that connected the Missouri River to valleys in Oregon and locations in between.After 1840 steam-powered riverboats and steamboats traversing up and down the Ohio, Mississippi and Missouri rivers sped settlement and development in the flat...
and was often the last mountain range American pioneers had to cross before reaching either southeast Washington near
Walla WallaWalla Walla is the largest city in and the county seat of Walla Walla County, Washington, United States. The population was 31,731 at the 2010 census...
or passing down the
Columbia River GorgeThe Columbia River Gorge is a canyon of the Columbia River in the Pacific Northwest of the United States. Up to deep, the canyon stretches for over as the river winds westward through the Cascade Range forming the boundary between the State of Washington to the north and Oregon to the south...
to end of the Oregon Trail in the
Willamette ValleyThe Willamette Valley is the most populated region in the state of Oregon of the United States. Located in the state's northwest, the region is surrounded by tall mountain ranges to the east, west and south and the valley's floor is broad, flat and fertile because of Ice Age conditions...
near
Oregon CityOregon City was the first city in the United States west of the Rocky Mountains to be incorporated. It is the county seat of Clackamas County, Oregon...
. The range today is traversed by Interstate 84, which crosses the crest of the range at a 4193 feet (1,278 m) summit, from south-southeast to north-northwest between
La Grande-Demographics:As of the census of 2000, there were 12,327 people, 5,124 households, and 2,982 families residing in the city. The population density was 2,833.5 people per square mile . There were 5,483 housing units at an average density of 1,260.3 per square mile...
and
PendletonPendleton is a city in Umatilla County, Oregon, United States. Pendleton was named in 1868 by the county commissioners for George H. Pendleton, Democratic candidate for Vice-President in the 1864 presidential campaign. The population was 16,612 at the 2010 census...
. The community of
Baker CityBaker City is a city in and the county seat of Baker County, Oregon, United States. It was named after Edward D. Baker. The population was 9,828 at the 2010 census.-History:...
sits along the southeastern flank of the range. U.S. Route 26 crosses the southern portion of the range, reaching a summit of 5098 feet (1,553.9 m) at
Blue Mountain PassBlue Mountain Pass is a high mountain pass in Oregon, United States through the Blue Mountains traversed by U.S. Highway 395....
.
Much of the range is included in the
Malheur National ForestThe Malheur National Forest is a National Forest in the U.S. state of Oregon. It contains 1.7 million acres in the Blue Mountains of eastern Oregon. The forest include high desert grasslands, sage, juniper, pine, fir, and other tree species. Elevations vary from about 4000 feet to the 9038...
,
Umatilla National ForestThe Umatilla National Forest, in the Blue Mountains of northeast Oregon and southeast Washington, covers an area of 1.4 million acres . In descending order of land area the forest is located in parts of Umatilla, Grant, Columbia, Morrow, Wallowa, Union, Garfield, Asotin, Wheeler, and Walla Walla...
, and Wallowa–Whitman National Forest. Several wilderness areas encompass remote parts of the range, including the Umatilla Wilderness, the
North Fork John Day WildernessThe North Fork John Day Wilderness is a wilderness area within the Umatilla and Wallowa-Whitman National Forests, in the Blue Mountains of northeastern Oregon....
,
Strawberry Mountain WildernessStrawberry Mountain Wilderness is a wilderness area of the Strawberry Mountain Range, within Malheur National Forest in the Blue Mountains of east Oregon. The area comprises , including mountain peaks and several lakes, and contains more than of hiking trails...
,
Monument Rock WildernessThe Monument Rock Wilderness Area is a wilderness area within the Malheur and Wallowa-Whitman National Forests in Blue Mountains of eastern Oregon. It was designated by the United States Congress in 1984 and comprises...
, all of which are in Oregon. The Wenaha–Tucannon Wilderness sits astride the Oregon-Washington border.
The range is drained by several rivers, including the
Grand RondeThe Grande Ronde River is a tributary of the Snake River, long, in northeastern Oregon and southeastern Washington in the United States. It drains an area southeast of the Blue Mountains and northwest of the Wallowa Mountains, on the Columbia Plateau...
and
TucannonThe Tucannon River is a river in southeastern Washington state that flows from headwaters in the Blue Mountains to a confluence with the Snake River upstream from Lyons Ferry Park and the mouth of the Palouse River. The Tucannon itself drains and is long...
, tributaries of the Snake, as well as the forks of the
John DayThe John Day River is a tributary of the Columbia River, approximately long, in northeastern Oregon in the United States. Undammed along its entire length, the river is the third longest free-flowing river in the conterminous United States. There is extensive use of its waters for irrigation. Its...
,
UmatillaThe Umatilla River is an tributary of the Columbia River in the U.S. state of Oregon. Draining a basin of , it enters the Columbia near the city of Umatilla in the northeastern part of the state...
and
Walla WallaThe Walla Walla River is a tributary of the Columbia River, joining the Columbia just above Wallula Gap in southeastern Washington in the United States. The river flows through Umatilla County, Oregon and Walla Walla County, Washington. Its drainage basin is in area.-Course:The headwaters of the...
rivers, tributaries of the
ColumbiaThe Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...
.