The
Marin Hills are a series of steep high ridges and peaks in southern Marin County. They are a part of the long
Pacific Coast RangesThe Pacific Coast Ranges and the Pacific Mountain System are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico...
mountainImage:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...
system. The centerpoint of these hills is the 2,571 foot (784 m)
Mount TamalpaisMount Tamalpais is a peak in Marin County, California, United States, often considered symbolic of Marin County. Much of Mount Tamalpais is protected within public lands such as Mount Tamalpais State Park and the Mount Tamalpais Watershed.-Geography:...
near Mill Valley. The hills are bordered to the north by the Santa Rosa Plain and
Laguna de Santa RosaThe Laguna de Santa Rosa is a long wetland complex that drains a 254-square mile watershed encompassing most of the Santa Rosa Plain in Sonoma County, California, USA.-Description:...
; to the east by
San Pablo BaySan Pablo Bay is a tidal estuary that forms the northern extension of San Francisco Bay in northern California in the United States. Most of the Bay is shallow; however, there is a deep water channel approximately in mid bay, which allows access to Sacramento, Stockton, Benicia, Martinez, and...
, the northern arm of
San Francisco BaySan Francisco Bay is a shallow, productive estuary through which water draining from approximately forty percent of California, flowing in the Sacramento and San Joaquin rivers from the Sierra Nevada mountains, enters the Pacific Ocean...
; to the south by Golden Gate Strait; and to the west by the
San Andreas FaultThe San Andreas Fault is a continental strike-slip fault that runs a length of roughly through California in the United States. The fault's motion is right-lateral strike-slip...
, running through
Tomales BayTomales Bay is a long narrow inlet of the Pacific Ocean in Marin County in northern California in the United States. It is approximately 15 miles long and averages nearly 1.0 miles wide, effectively separating the Point Reyes Peninsula from the mainland of Marin County. It is located...
,
Olema ValleyOlema Valley is a gorge formed by the San Andreas Fault in rural west Marin County, Northern California. The valley runs from the town of Olema through Dogtown and Point Reyes to the Bolinas Lagoon, which lies between Bolinas and Stinson Beach near Drake's Bay....
,
Bolinas LagoonBolinas Lagoon is a tidal estuary, approximately in area, located at in the West Marin region of Marin County, California, United States. It is a part of the Gulf of the Farallones National Marine Sanctuary. The lagoon is a back bay of Bolinas Bay on the Pacific coast approximately 15 mi ...
, and
Stinson BeachStinson Beach is a census-designated place in Marin County, California, on the west coast of the United States. Stinson Beach is located east-southeast of Bolinas, at an elevation of 26 feet . The population of the Stinson Beach CDP was 632 at the 2010 census.Stinson Beach is about a 35-minute...
. Parts of the hills are protected for their scenic beauty by
Mount Tamalpais State ParkMount Tamalpais State Park is a California state park, located in Marin County, California. The primary feature of the park is the Mount Tamalpais. The park contains mostly redwood and oak forests. The mountain itself covers around . There are about of hiking trails, which are connected to a...
and the
Golden Gate National Recreation AreaThe Golden Gate National Recreation Area is a U.S. National Recreation Area administered by the National Park Service that surrounds the San Francisco Bay area. It is one of the most visited units of the National Park system in the United States, with over 13 million visitors a year...
. The many ridges and peaks of these hills form a dramatic backdrop to the
Golden Gate BridgeThe Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the opening of the San Francisco Bay into the Pacific Ocean. As part of both U.S. Route 101 and California State Route 1, the structure links the city of San Francisco, on the northern tip of the San Francisco Peninsula, to...
, the
San FranciscoSan Francisco , officially the City and County of San Francisco, is the financial, cultural, and transportation center of the San Francisco Bay Area, a region of 7.15 million people which includes San Jose and Oakland...
skyline, and several towns around
Richardson BayRichardson Bay is a shallow, ecologically rich arm of San Francisco Bay, managed under a Joint Powers Agency of four Northern California cities. The Richardson Bay Sanctuary was acquired in the early 1960s by the National Audubon Society. The bay was named for William A...
when viewed from the south.
Climate
Since these hills lie near the
Pacific OceanThe 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...
, they force much of the incoming moisture out of the air and rainfall here is much greater than the bayside of Marin County. Due to this orographic rain effect, the
Marin Municipal Water DistrictThe Marin Municipal Water District is the government agency that provides drinking water to southern and central Marin County, California. Chartered in 1912, it became California's first municipal water district...
has constructed several dams and
reservoirA reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...
s to store water for the population of Marin. The high rainfall also makes these hills conducive for Coast redwood and
Douglas-firDouglas-fir is one of the English common names for evergreen coniferous trees of the genus Pseudotsuga in the family Pinaceae. Other common names include Douglas tree, and Oregon pine. There are five species, two in western North America, one in Mexico, and two in eastern Asia...
. However, a side effect is that the eastern hills, where most of Marin's population lives, are drier and hotter due to the shielding of marine breezes. The low hills to the east support only
California oak woodlandCalifornia oak woodland is a plant community found throughout the California chaparral and woodlands ecoregion of California in the United States and northwestern Baja California in Mexico...
s, chapparal and
grasslandGrasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s.
Landscape
The western part of the hills hills once had extensive old growth forests, but in the 1800s they were a source of timber for the
San Francisco Bay AreaThe San Francisco Bay Area, commonly known as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas of San Francisco, Oakland, and San Jose, along with smaller urban and rural areas...
, and thus logging took out most of the old growth stands; however, one old growth stand remained uncut in Sequoia Canyon, due to the steep terrain and it therefore withstood pressure from loggers and water companies. This stand is now the
Muir Woods National MonumentMuir Woods National Monument is a unit of the National Park Service on the Pacific coast of southwestern Marin County, California, north of San Francisco and part of the Golden Gate National Recreation Area...
, part of the
Golden Gate National Recreation AreaThe Golden Gate National Recreation Area is a U.S. National Recreation Area administered by the National Park Service that surrounds the San Francisco Bay area. It is one of the most visited units of the National Park system in the United States, with over 13 million visitors a year...
. The parklands of these hills are popular with tourists and locals alike seeking to escape the urban areas of the Bay Area.