The Colorado Territory was created on February 28, 1861, Arapahoe County was formed on November 1, 1861, and Denver City was incorporated on November 7, 1861. Denver City served as the Arapahoe County Seat from 1861 until consolidation in 1902. In 1867, Denver City became the territorial capital. With its newfound importance, Denver City shortened its name to Denver. On August 1, 1876, Colorado was admitted to the Union.
According to the 2010 census, the City and County of Denver contained 600,158 people and 285,797 households. The population density was 3,698 inhabitants per square mile (1,428/km²) including the airport. There were 285,797 housing units at an average density of 1,751 per square mile (676/km²). However, the average density throughout most Denver neighborhoods tends to be higher. Without the 80249 zip code (47.3 sq mi, 8,407 residents) near the airport, the average density increases to around 5,470 per square mile. Denver, Colorado, is at the top of the list of 2017 Best Places to Live, according to U.S. News & World Report, landing a place in the top two in terms of affordability and quality of lifestyle.