Colorado, State, west-central U.S. Area: 104,094 sq mi (269,603 sq km). Population: (2020) 5,773,714; (2023 est.) 5,877,610. Capital: Denver. Colorado is bordered by Wyoming, Nebraska, Kansas, Oklahoma, New Mexico, and Utah. Lying astride the Rocky Mountains, the state has three physiographic regions: the plains, a semiarid segment of eastern Colorado; the Colorado Piedmont in the central part of the state, where most of the population lives; and the southern Rocky Mountains and mesas of western Colorado. Its original inhabitants were Plains and Great Basin Indians, including the Arapaho, Cheyenne, and Ute. U.S. exploration of Colorado began immediately after the United States made the Louisiana Purchase, of which Colorado was a part, in 1803. Gold was discovered in 1858 and touched off a gold rush and population boom beginning the following year. Organized as the territory of Colorado in 1861, it achieved U.S. statehood in 1876. Agriculture, cattle production, and mining, as well as manufacturing, are important to the economy. Government military installations and service industries have become prominent, and tourism is a major source of the state’s income (see Aspen; Boulder; Vail).
