The State of Colorao (pronounced /ˌkɒləˈrædoʊ/ or, chiefly by outsiders, /ˌkɒləˈrɑːdoʊ/) is a state located in the Rocky Mountain region of the United States of America. Colorado may also be considered to be a part of the Western and Southwestern regions of the United States. The United States Census Bureau estimates that the state population was 4,861,515 in 2007, a 13.03% increase since the U.S. Census 2000.Denver is the capital as well as the most populous city of Colorado. Citizens of Colorado are known as Coloradans.