Wyoming is a state in the mountain region of the Western United States. Wyoming is the 10th most extensive, but the least populous and the
second least densely populated of the
50 United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High Plains. As specified in the designating legislation for the
Territory of Wyoming, Wyoming's borders are lines of latitude, 41°N and 45°N, and longitude, 104°3'W and 111°3'W (27° W and 34° W of the
Washington Meridian), making the shape of the state a latitude-longitude quadrangle. Wyoming is one of only three states (along with Colorado and Utah) to have borders along only straight latitudinal and longitudinal lines, rather than being defined by natural landmarks. Due to surveying inaccuracies during the 19th century, Wyoming's legal border deviates from the true latitude and longitude lines by up to half of a mile (0.8 km) in some spots, especially in the mountainous region along the 45th parallel. Wyoming is bordered on the north by Montana, on the east by South Dakota and Nebraska, on the south by Colorado, on the southwest by Utah, and on the west by Idaho. It is the tenth largest state in the United States in total area, containing 97,814 square miles (253,340 km
2) and is made up of 23 counties. From the north border to the south border it is 276 miles (444 km); and from the east to the west border is 365 miles (587 km) at its south end and 342 miles (550 km) at the north end.
The Great Plains meet the Rocky Mountains in Wyoming. The state is a great plateau broken by many mountain ranges. Surface elevations range from the summit of Gannett Peak in the Wind River Mountain Range, at 13,804 feet (4,207 m), to the Belle Fourche River valley in the state’s northeast corner, at 3,125 feet (953 m). In the northwest are the Absaroka, Owl Creek, Gros Ventre, Wind River and the Teton ranges. In the north central are the Big Horn Mountains; in the northeast, the Black Hills; and in the southern region the Laramie, Snowy and Sierra Madre ranges.
The Snowy Range in the south central part of the state is an extension of the Colorado Rockies in both geology and appearance. The Wind River Range in the west central part of the state is remote and includes more than 40 mountain peaks in excess of 13,000 ft (4,000 m) tall in addition to Gannett Peak, the highest peak in the state. The Big Horn Mountains in the north central portion are somewhat isolated from the bulk of the Rocky Mountains.
The Teton Range in the northwest extends for 50 miles (80 km), part of which is included in Grand Teton National Park. The park includes the Grand Teton, the second highest peak in Wyoming.
The Continental Divide spans north-south across the central portion of the state. Rivers east of the divide drain into the Missouri River Basin and eventually the Gulf of Mexico. They are the North Platte, Wind, Big Horn and the Yellowstone rivers. The Snake River in northwest Wyoming eventually drains into the Columbia River and the Pacific Ocean, as does the Green River through the Colorado River Basin.
The continental divide forks in the south central part of the state in an area known as the Great Divide Basin where the waters that flow or precipitate into this area remain there and cannot flow to any ocean. Instead, because of the overall aridity of Wyoming, water in the Great Divide Basin simply sinks into the soil or evaporates.
Several rivers begin or flow through the state, including the Yellowstone River, Bighorn River, Green River, and the Snake River.
Wyoming has 32 named islands, of which the majority are located in Jackson Lake and Yellowstone Lake within Yellowstone National Park in the northwest portion of the state. Green River in the southwest also contains a number of islands.
More than 48% of the land in Wyoming is owned by the U.S. Government, leading Wyoming to rank sixth in the U.S. in total acres and fifth in percentage of a state's land owned by the federal government. This amounts to about 30,099,430 acres (121,808.1 km2) owned and managed by the U.S. Government. The state government owns an additional 6% of all Wyoming lands, or another 3,864,800 acres (15,640 km2).
The vast majority of this government land is managed by the Bureau of Land Management and U.S. Forest Service in numerous National Forests, a National Grassland, and a number of vast swaths of public land, in addition to the F.E. Warren Air Force Base in Cheyenne.