Wyoming (/waɪˈoʊmɪŋ/ (listen)) is a state in the Mountain West region of the United States. The 10th largest state by area, it is also the least populous and least densely populated state in the contiguous United States.^[a] It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the south. 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.^[6]

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. It is drier and windier than the rest of the country, being split between semi-arid and continental climates with greater temperature extremes. Almost half of the land in Wyoming is owned by the federal government, leading the state to rank sixth by area and fifth by proportion of a state's land owned by the federal government.^[7] 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.