The City and County of Denver is the capital and the most populous city of the state of Colorado, in the United States. Denver is a consolidated city-county located in the South Platte River Valley on the High Plains just east of the Front Range of the Rocky Mountains. Denver is nicknamed the Mile-High City because its’ official elevation is exactly one mile, or 5,280 feet (1,609 m) above sea level. The United States Census Bureau estimated that the population of Denver was 598,707 in 2008, making it the 24th most populous U.S. city.