Wyoming (state)

I

Introduction

Wyoming (state), in the western United States. It is bordered by Montana on the north, South Dakota and Nebraska on the east, Colorado and Utah on the south, and Utah, Idaho, and Montana on the west. The land within these borders was first called Wyoming in 1865, when a member of the Congress of the United States from Ohio suggested that a new territory be carved from Dakota, Utah, and Idaho territories.

The name Wyoming is a contraction of the Native American word mecheweamiing (“at the big plains”), and was first used by the Delaware people as a name for the Wyoming Valley in northeastern Pennsylvania. Wyoming is known as the Cowboy State and the Equality State. The latter recognizes Wyoming as the first state to specifically give women the right to vote, which it did as a territory in 1869 and retained upon entering the Union. Cheyenne is Wyoming’s capital and largest city.

Wyoming became a territory in 1868 and entered the Union on July 10, 1890, as the 44th state. It has a wealth of mineral and agricultural resources, and mining and agriculture still play major roles in the state’s economy. The state is thinly populated and ranks 50th among the 50 states in population. Wyoming is a place of great natural beauty, and each year large numbers of tourists are attracted by the state’s unspoiled scenic wonders.

II

Physical Geography

Wyoming ranks ninth in size among the states of the Union, covering 253,337 sq km (97,814 sq mi), including 1,847 sq km (713 sq mi) of inland water. The state has a maximum extent from east to west of 586 km (364 mi) and from north to south of 444 km (276 mi). About one-third of the state is mountainous. Elevations range from 945 m (3,099 ft) along the Belle Fourche River in the northeastern corner of the state to 4,207 m (13,804 ft) atop Gannett Peak in the Wind River Range, part of the Rocky Mountains. The mean elevation is 2,040 m (6,700 ft).

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A

Natural Regions

Wyoming contains parts of four major natural regions, or physiographic provinces, of the United States: the Southern Rocky Mountains, the Wyoming Basins, the Middle Rocky Mountains, and the Great Plains. The first three are subdivisions of a broader region known as the Rocky Mountain System (see Rocky Mountains); the Great Plains are part of the Interior Plains.

The Great Plains cover most of the eastern third of the state in a strip that broadens from south to north. It is an upland plateau, generally undulating, and in places broken by rough topography, low hills, and isolated buttes. The Black Hills of South Dakota extend into the northeastern corner of the state, their outstanding physical feature being Devils Tower, a volcanic neck vaulting 390 m (1,280 ft) from the floor of the surrounding valley.

Farther south three ranges of the Southern Rocky Mountains extend pronglike into Wyoming from their main massif in Colorado. They are the Laramie Mountains, about 230 km (about 140 mi) long, bordering the Great Plains; the Medicine Bow Mountains, about 80 km (about 50 mi) long, slightly to the west; and the Sierra Madre, about 50 km (about 30 mi) long, even farther west.

The Wyoming Basins, in central Wyoming, comprise a high arid plateau ringed by mountains, except on the northeast, where the region opens out on the Great Plains through a broad gap between the Southern and Middle Rocky Mountains. The basins together cover a somewhat larger area of the state than the Great Plains. General elevations range from 1,800 to 2,300 m (6,000 to 7,500 ft). The region is actually a series of basins broken up by low ridges. Far more striking than the ridges, which rarely rise more than 300 m (1,000 ft) above the surface, are the deep canyons carved in the landscape by millions of years of erosion by streams and rivers originating in the nearby mountains. The basins are drained northward by the Bighorn River, eastward by the North Platte River, and southward by the Green River.

The Continental Divide passes through the Wyoming Basins, but it splits west of Rawlins. The two arms of the divide come together again near the Wind River Mountains, forming the Great Divide Basin. Water in the Great Divide Basin flows to a series of salt flats and ponds in an area known as the Chain-of-Lakes, not to the Atlantic or Pacific oceans. The Continental Divide is essentially treeless in this area, dominated by native shrubs such as sagebrush, greasewood, and saltbush. North America’s largest area of active sand dunes occurs in the region, extending in a linear pattern from northeast of Rock Springs across the Great Divide Basin to south of the Ferris Mountains north of Rawlins.

The Middle Rocky Mountains occupy the northwestern quarter of the state and include the Bighorn, Owl Creek, Gros Ventre, Wind River, Absaroka, and Teton ranges. The highest point in this spectacularly beautiful region is Gannett Peak, in the Wind River Range. The Tetons are some of the most precipitous mountains on the North American continent, rising abruptly along a 60-km (40-mi) front near Wyoming’s western border, with many peaks rising above 3,000 m (10,000 ft). The highest is the Grand Teton, rising 4,197 m (13,771 ft). In the northwestern corner of Wyoming is Yellowstone National Park, a volcanic area containing about 3,000 hot springs and geysers and scored deeply at the Grand Canyon of the Yellowstone River. East of the park lies the sheltered, mountain-ringed Bighorn Basin.

B

Rivers and Lakes

Straddling the Continental Divide, Wyoming is a source area for the waters of the four main drainage systems of the western United States: the Missouri-Mississippi; the Interior, or Great Basin; the Columbia; and the Colorado. Rivers joining the Missouri include the Yellowstone, Bighorn, Powder, and Belle Fourche rivers, which flow north, and the North Platte River, with such tributaries as the Sweetwater and Laramie rivers, which flow east. The Green River, rising in the Wind River Range, drains the greater part of southwestern Wyoming before joining the Colorado. The upper Bear River basin, part of the Interior Basin system, occupies a small section along the western border of the state. Northwestern Wyoming is drained by the Snake River, a major tributary of the Columbia.

The largest natural lake in Wyoming and probably the largest at its altitude (2,357 m/7,733 ft) anywhere in the United States is Yellowstone Lake, which covers an area of 339 sq km (131 sq mi) and has a maximum depth of 98 m (320 ft). Just to the south lies the second largest lake in Wyoming, Jackson Lake, with an area of about 100 sq km (about 40 sq mi). Jackson Lake has been enlarged by a dam on the Snake River. Fremont Lake, located north of Pinedale, is one of the state’s most spectacular lakes and was formed by glaciers that retreated as the climate warmed about 12,000 years ago. Some of Wyoming’s reservoirs are also of impressive size, especially the reservoir on the Green River created by Flaming Gorge Dam.

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