The State of Colorado is a state located in the Rocky Mountain region of the United States of America.
On February 28, 1861, outgoing U.S. President James Buchanan signed an act of Congress organizing the free Territory of Colorado. On August 1, 1876 (28 days after Centennial of the United States), U.S. President Ulysses S. Grant signed a proclamation admitting the State of Colorado to the Union as the 38th state and earning it the moniker the "Centennial State".
The state's largest city, and capital, is Denver. The Denver-Aurora-Boulder Combined Statistical Area, home to 2,927,911 people, contains more than two-thirds of the state's population. Residents of Colorado are referred to as Coloradans.
The territory that ultimately became Colorado was added to the United States by the 1803 Louisiana Purchase and the 1848 Mexican Cession.
In 1854, the Kansas Territory was organized, including what is now much of Colorado.
The Pike's Peak Gold Rush of 1859 brought many settlers to the Denver area. A convention was held to organize the provisional Jefferson Territory, but an official break from the Kansas Territory did not happen until 1861.
The Colorado Territory was organized as a United States territory on 28 February 1861, with President Buchanan signing an Act of Congress to that effect.
Colorado attained statehood on 1 August 1876, earning it the moniker the "Centennial State".