Get the auto license in Colorado. Denver is City and County and is the capital and most populous city in the U.S. state of Colorado. Denver is a consolidated city-county located in the valley south of the Platte River on the western edge of the High Plains just east of the Rocky Mountains range front. The district of downtown Denver is located just east of the confluence of Cherry Creek with the South Platte River, about 12 miles (19 km) east of the Rocky Mountain foothills. Denver is nicknamed the Mile-High City as the official height is exactly one mile (1.6 kilometers) or 5280 feet (1609.344 m) above sea level. The 105th Meridian west of Greenwich passes through Union Station, and the time reference for the Mountain time zone.