Wyoming () is a landlocked state in the western United States. The 10th largest state by area, it is also the least populous and second most sparsely populated state in the country. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Colorado to the south, Utah to the southwest, and Idaho to the west. The state population was estimated at 578,759 in 2019. The state capital and the most populous city is Cheyenne, which had an estimated population of 63,957 in 2018.

Wyoming’s western half is mostly covered by the ranges and rangelands of the Rocky Mountains, while the eastern half of the state is high-elevation prairie called the High Plains. Almost half of the land in Wyoming is owned by the U.S. government, leading Wyoming to rank sixth by area and fifth by proportion of a state’s land owned by the federal government. Federal lands include two national parks—Grand Teton and Yellowstone—two national recreation areas, two national monuments, several national forests, historic sites, fish hatcheries, and wildlife refuges.

Original inhabitants of the region include the Arapaho, Crow, Lakota, and Shoshone. Southwest Wyoming was claimed by the Spanish Empire and then as Mexican territory until it was ceded to the U.S. in 1848 at the end of the Mexican–American War. The region acquired the name “Wyoming” when a bill was introduced to Congress in 1865 to provide a temporary government for the territory of Wyoming. The name had been used earlier for the Wyoming Valley in Pennsylvania, and is derived from the Munsee word xwé:wamənk, meaning “at the big river flat”.

The main drivers of Wyoming’s economy are tourism and extraction of minerals such as coal, oil, natural gas, and trona. Agricultural commodities include livestock, hay, sugar beets, grain (wheat and barley), and wool. The climate is semi-arid and continental, drier and windier than the rest of the country with greater temperature extremes. Wyoming has been a politically conservative state since the 1950s, with the Republican nominee carrying the state in every presidential election since 1968.