The Blue Mountains are a

mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have ari ...

in the northwestern

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

, located largely in northeastern

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

and stretching into extreme southeastern

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

. The range has an area of about , stretching east and southeast of

Pendleton, Oregon Pendleton is a city and the county seat of Umatilla County, Oregon. The population was 17,107 at the time of the 2020 census, which includes approximately 1,600 people who are incarcerated at Eastern Oregon Correctional Institution. Pendleton ...

, to the

Snake River The Snake River is a major river of the greater Pacific Northwest region in the United States. At long, it is the largest tributary of the Columbia River, in turn, the largest North American river that empties into the Pacific Ocean. The Snake ...

along the Oregon–

Idaho Idaho ( ) is a U.S. state, state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Monta ...

border. The Blue Mountains cover ten counties across two states; they are Union, Umatilla,

Grant Grant or Grants may refer to: Places *Grant County (disambiguation) Australia * Grant, Queensland, a locality in the Barcaldine Region, Queensland, Australia United Kingdom * Castle Grant United States * Grant, Alabama * Grant, Inyo County, ...

Baker A baker is a tradesperson who baking, bakes and sometimes Sales, sells breads and other products made of flour by using an oven or other concentrated heat source. The place where a baker works is called a bakery. History Ancient history Si ...

Wallowa Wallowa may refer to: Places * Wallowa, Oregon *Wallowa County, Oregon *Wallowa Lake * Wallowa Lake State Park *Wallowa Mountains *Wallowa River Other *'' Acacia calamifolia'', a shrub or tree *'' Acacia euthycarpa'', a shrub or tree * '' The ...

and Harney counties in Oregon, and Walla Walla,

Columbia Columbia may refer to: * Columbia (personification), the historical female national personification of the United States, and a poetic name for America Places North America Natural features * Columbia Plateau, a geologic and geographic region i ...

Garfield ''Garfield'' is an American comic strip created by Jim Davis. Originally published locally as ''Jon'' in 1976, then in nationwide syndication from 1978 as ''Garfield'', it chronicles the life of the title character Garfield the cat, his hum ...

and Asotin counties in Washington. The mountains are unique as the home of the world's largest living organism, a subterranean colonial mycelial mat of the fungus '' Armillaria ostoyae''. The Blue Mountains were named after the color of the mountains when seen from a distance.

Geology

The Blues are

uplift mountains Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted t ...

cbgwma.or
The Columbia River Basalt Group , Continental flood basalt flows , cbgwma.org
accessdate: February 8, 2017 and contain some of the oldest rocks in Oregon. Rocks as old as 400 million years protrude through surrounding Columbia River Basalt flows of 52 million to 6 million years ago.

Geologically Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other E ...

, the Blue Mountains were created as an

island arc Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle alon ...

in the Pacific Ocean and accreted onto the

North American plate The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Paci ...

. Within these terranes are

igneous intrusions Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...

which may have intruded before or after accretion. They are made up of several mountain ranges, from the

Ochoco Mountains The Ochoco Mountains are a mountain range in central Oregon in the United States, located at the western end of the Blue Mountains. They were formed when Permian, Triassic, and Jurassic rocks were slowly uplifted by volcanic eruptions to form ...

and

Maury Mountains The Maury Mountains are a mountain range in Crook County, Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washingt ...

in the west near

Prineville, Oregon Prineville is a city in and the seat of Crook County, Oregon, United States. It was named for the first merchant located in the present location, Barney Prine. The population was 9,253 at the 2010 census. History Prineville was founded in 187 ...

, through the

Greenhorn Mountains The Greenhorn Mountains are a mountain range of the Southern Sierra Nevada, in California. They are protected within the Sequoia National Forest. Geography The range is located in eastern Kern County and Tulare County. They are east of the San ...

, the Aldrich Mountains, and the

Strawberry Range The Strawberry Range, also known as the Strawberry Mountains, is a mountain range in the U.S. state of Oregon. It is east of John Day, within Malheur National Forest. The highest peak is Strawberry Mountain. The Strawberry Range is part of th ...

, to the

Elkhorn Mountains The Elkhorn Mountains are a mountain range in southwestern Montana, part of the Rocky Mountains and are roughly 300,000 acres (1200 km²) in size. It is an inactive volcanic mountain range with the highest point being Crow Peak at , right n ...

. The tallest peaks are Rock Creek Butte at in the Elkhorn Mountains, and Strawberry Mountain at in the Strawberry Range.

History

Habitation by Native Americans

The river valleys and lower levels of the range were occupied by indigenous peoples for thousands of years. Historic tribes of the region included the Walla Walla, Cayuse people and Umatilla, now acting together as the

Confederated Tribes of the Umatilla Indian Reservation The Confederated Tribes of the Umatilla Indian Reservation are the federally recognized confederations of three Sahaptin-speaking Native American tribes who traditionally inhabited the Columbia River Plateau region: the Cayuse, Umatilla, and ...

, located mostly in Umatilla County, Oregon. The southern portion of the Blue Mountains were inhabited by several different bands of the

Northern Paiute Northern may refer to the following: Geography * North, a point in direction * Northern Europe, the northern part or region of Europe * Northern Highland, a region of Wisconsin, United States * Northern Province, Sri Lanka * Northern Range, a ...

, a

Great Basin The Great Basin is the largest area of contiguous endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California. It is noted fo ...

culture. Native American tribes originally migrated to the Blue Mountains for hunting and salmon runs. The Natives used to purposefully burn small parts of the forest in order to create pastures to attract game for hunting.

During westward expansion of the United States

In the mid-1800s, the Blue Mountains were a formidable obstacle to settlers traveling on the

Oregon Trail The Oregon Trail was a east–west, large-wheeled wagon route and emigrant trail in the United States that connected the Missouri River to valleys in Oregon. The eastern part of the Oregon Trail spanned part of what is now the state of Kans ...

and were often the last mountain range American pioneers had to cross before either reaching southeast Washington near Walla Walla or passing down the

Columbia River Gorge The 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 st ...

to the end of the Oregon Trail in the

Willamette Valley The Willamette Valley ( ) is a long valley in Oregon, in the Pacific Northwest region of the United States. The Willamette River flows the entire length of the valley and is surrounded by mountains on three sides: the Cascade Range to the eas ...

near

Oregon City ) , image_skyline = McLoughlin House.jpg , imagesize = , image_caption = The McLoughlin House, est. 1845 , image_flag = , image_seal = Oregon City seal.png , image_map ...

Modern travel

The range is currently traversed by Interstate 84, which crosses the crest of the range at a summit, from south-southeast to north-northwest between La Grande and Pendleton. The community of

Baker City Baker City is a city in and the county seat of Baker County, Oregon, United States. It was named after Edward D. Baker, the only U.S. Senator ever killed in military combat. The population was 10,099 at the time of the 2020 census. History Pla ...

is located along the south-eastern flank of the range. U.S. Route 26 crosses the southern portion of the range, traversing the Blue Mountain Summit and reaching an elevation of . It is also crossed by the

Union Pacific Railroad The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...

's mainline between Portland, Oregon, and Pocatello, Idaho, which crests the summit at

Kamela, Oregon Kamela is an unincorporated community in Union County, Oregon, United States.(no longer supported) It is located west of Interstate 84 about 20 miles northwest of La Grande. There are several stories about how the community got its name. Among ...

. The summit lies on Union Pacific's La Grande Subdivision, which runs between La Grande and Hinkle, the latter of which is the site of a major UP yard.

Wildlife

Birds of the area include

bald eagle The bald eagle (''Haliaeetus leucocephalus'') is a bird of prey found in North America. A sea eagle, it has two known subspecies and forms a species pair with the white-tailed eagle (''Haliaeetus albicilla''), which occupies the same niche as ...

northern spotted owl The northern spotted owl (''Strix occidentalis caurina'') is one of three spotted owl subspecies. A western North American bird in the family Strigidae, genus '' Strix'', it is a medium-sized dark brown owl native to the Pacific Northwest. An ...

, Lewis's woodpecker,

Williamson's sapsucker Williamson's sapsucker (''Sphyrapicus thyroideus'') is a medium-sized woodpecker belonging to the genus '' Sphyrapicus'' (sapsuckers). Habitat and range Breeding habitat is open forested areas with conifers, mainly ponderosa pine, douglas-fi ...

red-breasted nuthatch The red-breasted nuthatch (''Sitta canadensis'') is a small songbird. The adult has blue-grey upperparts with cinnamon underparts, a white throat and face with a black stripe through the eyes, a straight grey bill and a black crown. Its call, wh ...

, golden-crowned kinglet and many migratory species, with the riverbanks important habitat for this birdlife. Mammals that move through the mountain grasslands include Rocky Mountain elk (including the largest herd in North America at Hells Canyon),

Bighorn sheep The bighorn sheep (''Ovis canadensis'') is a species of sheep native to North America. It is named for its large horns. A pair of horns might weigh up to ; the sheep typically weigh up to . Recent genetic testing indicates three distinct subsp ...

and

Mule deer The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer. Unlike the related whi ...

. Native fish include Chinook Salmon, Steelhead, Redband Trout, Coho Salmon, Bull Trout, and Pacific Lamprey. The Blue Mountains in Washington are home to one of 10 identified elk herds in the state, with a population of approximately 4,500 Rocky Mountain elk as of 2018 across the region. In 1989, in response to a decline in the elk population and a heavy female-biased population, the Washington Fish & Wildlife Department regulated elk hunting in the Washington Blue Mountains with a "spike-only" general hunting season, permitting hunting of only male elk with at least one visible non-branched antler. By the mid 1990s the area then became known for its mature males and trophy hunting. In 2018, Washington State proposed an updated elk management plan intended to improve the health of elk populations and habitats, reduce human conflict and agricultural damage, and managing elk populations for recreational, educational, scientific, and ceremonial purposes. During winter months elk will prefer to use "moderately steep south slopes" rather than northern slopes because of the southern slopes being warmer and containing less snow.

Land management

The public lands in the Blue Mountains are managed not only by the United States Forest Service and the Bureau of Land Management, but also by land owners and the Confederated Tribes of the Umatilla Indian Reservation.

Location

Much of the range is included in the Malheur National Forest,

Umatilla National Forest The Umatilla National Forest, in the Blue Mountains of northeast Oregon and southeast Washington, covers an area of 1.4 million acres (5,700 km2). In descending order of land area the forest is located in parts of Umatilla, Grant, Columbia ...

, and Wallowa–Whitman National Forest. Several wilderness areas encompass remote parts of the range, including the North Fork Umatilla Wilderness, the

North Fork John Day Wilderness The North Fork John Day Wilderness is a wilderness area within the Umatilla and Wallowa–Whitman National Forests in the Blue Mountains of northeastern Oregon. The wilderness consists of four separate units: the main unit of the North Fork J ...

, the

Strawberry Mountain Wilderness Strawberry 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 ...

, and the

Monument Rock Wilderness The Monument Rock Wilderness Area is a wilderness area within the Malheur and Wallowa–Whitman national forests in the Blue Mountains of eastern Oregon. It was designated by the United States Congress in 1984 and comprises . There are appr ...

, all of which are in Oregon. The Wenaha–Tucannon Wilderness sits astride the Oregon–Washington border.

Drainage

The range is drained by several rivers, including the Grande Ronde and Tucannon, tributaries of the Snake, as well as the forks of the John Day, Umatilla and Walla Walla rivers, tributaries of the

. The southernmost portion of the Blue Mountains is drained by the

Silvies River The Silvies River flows for about through Grant and Harney counties in the U.S. state of Oregon. The river drains of the northern Harney Basin. The headwaters are on the southern flank of the Aldrich Mountains, about south of Mount Vernon i ...

, in the endorheic Harney Basin.

References

External links

* {{Authority control Mountain ranges of Oregon Mountain ranges of Washington (state) Physiographic sections Landforms of Columbia County, Washington Landforms of Garfield County, Washington Mountain ranges of Grant County, Oregon Landforms of Wallowa County, Oregon Mountain ranges of Baker County, Oregon Landforms of Union County, Oregon Landforms of Umatilla County, Oregon Malheur National Forest Wallowa–Whitman National Forest Umatilla National Forest