Wyoming is a state in the western United States. The easternmost section of the state is a region known as the High Plains due to its altitude above sea level, while the majority of the state is dominated by the mountain ranges and rangelands of the Rocky Mountain West. Wyoming is the least populous U.S. state. The United States Census Bureau estimates that the state population was 515,004 in 2006, a 4.3% increase since 2000. The capital and the most populous city of Wyoming is Cheyenne. Residents of Wyoming are known as Wyomingites.