n.
State (pop., 2000: 4,301,261), west-central U.S. Bordered by Wyoming, Nebraska, Kansas, Oklahoma, New Mexico, and Utah, it covers 104,100 sq mi (269,619 sq km); its capital is Denver .
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 large urban population has grown faster than the national average. Its original inhabitants were Plains and Great Basin Indians, including the Arapaho , Cheyenne , and Ute . The area was claimed by Spain in 1706 but later passed in large part to France. Eastern Colorado was part of the Louisiana Purchase in 1803; the remainder stayed in Spanish and, after independence, Mexican hands until 1848. Gold was discovered in 1859 and touched off a population boom. 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 ).