Denver ( DEN-vər), officially the City and County of Denver, is the capital and most populous city of the U.S. state of Colorado. Officially a consolidated city and county, it is located in the South Platte River valley on the western edge of the High Plains, and is just east of the Front Range of the Rocky Mountains (Rockies). Denver is the 19th-most populous city in the United States and the fifth-most populous state capital, with a population of 715,522 at the 2020 census. The ten-county Denver metropolitan area, with 3.1 million residents, is the 19th-largest metropolitan area in the country and functions as the economic and cultural center of the broader Front Range Urban Corridor. Denver's downtown district lies about 12 miles (19 kilometers) east of the foothills of the Rocky Mountains. Named after James W. Denver, the governor of the Kansas Territory at the time, Denver was founded at the confluence of Cherry Creek and the South Platte River in 1858 during the Gold Rush era. Nicknamed the "Mile High City" because its official elevation is exactly one mile (5280 feet or 1609.344 meters) above sea level, Denver grew beyond its prospecting origins to become the principal commercial and transportation hub for a broad region spanning the Great Plains and Rocky Mountain West. The 105th meridian west of Greenwich, the longitudinal reference for the Mountain Time Zone, passes directly through Denver Union Station. As the most populous metropolitan area in a 560-mile (900 km) radius, Denver is a major cultural hub with a variety of museums and cultural institutions, including the Denver Performing Arts Complex, the Denver Art Museum and the Denver Museum of Nature and Science. Denver has professional sports teams in five leagues and hosts the headquarters of eight Fortune 500 firms.