Denver (), officially the City and County of Denver, is the capital and most populous municipality of the U.S. state of Colorado. Denver is located in the South Platte River Valley on the western edge of the High Plains just east of the Front Range of the Rocky Mountains. With an estimated population of 727,211 in 2019, Denver is the 19th-most populous city in the United States, the fifth-most populous state capitol, and the most populous city located in the Mountain states. The metropolitan area surrounding Denver represents a majority of the population and economic activity in the Front Range region, an area within which an estimated 85% of Colorado's population lives. The Denver downtown district is immediately east of the confluence of Cherry Creek with the South Platte River, approximately 12 mi (19 km) east of the foothills of the Rocky Mountains. Denver is named after James W. Denver, a governor of the Kansas Territory. It is nicknamed the Mile High City because its official elevation is exactly one mile (5280 feet or 1609.3 meters) above sea level. The 105th meridian west of Greenwich, the longitudinal reference for the Mountain Time Zone, passes directly through Denver Union Station. Denver is ranked as a Beta world city by the Globalization and World Cities Research Network. The 10-county Denver-Aurora-Lakewood, CO Metropolitan Statistical Area had an estimated 2018 population of 2,932,415 and was the 19th most populous U.S. metropolitan statistical area. The 12-city Denver-Aurora, CO Combined Statistical Area had an estimated 2018 population of 3,572,798 and was the 15th most populous U.S. metropolitan area. Denver was the most populous city of the 18-county Front Range Urban Corridor, an oblong urban region stretching across two states with an estimated 2018 population of 4,976,781. Denver is the most populous city within a 500-mile (800 km) radius and the second-most populous city in the Mountain West after Phoenix, Arizona. In 2016, Denver was named the best place to live in the United States by U.S. News & World Report.