The State of Wyoming is a sparsely populated state in the western region of the United States. The majority of the state is dominated by the mountain ranges and rangelands of the Rocky Mountain West, while the easternmost section of the state is a high altitude prairie region known as the High Plains. While the tenth largest U.S. state by size, Wyoming is the least populous, with a U.S. Census estimated population of 522,830 in 2007, a 5.9% increase since 2000. The capital and the most populous city of Wyoming is Cheyenne.
As specified in the designating legislation for the territory of Wyoming, the state is defined as a geoellipsoidal rectangle bounded by lines of latitude and longitude. Wyoming is only one of three states (along with Colorado and Utah) to have only lines of latitude and longitude for boundaries and that have no natural borders. In reality, due to survey errors during the 19th century, Wyoming's border deviates from the latitude or longitude lines by up to 1/2 mile (.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 97,818 square miles (253,348 km?) 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.