The human history of Colorado is as deep and rich as the Rocky Mountains that are the prominent feature of its landscape. For more than 13,000 years, Native Americans inhabited the region. Artifacts can be traced to major known peoples and tribes — Pueblo, Ute, Apache, Comanche, Arapaho, and Cheyenne are each known to have had an impactful presence in Colorado from the eastern edge of the Rockies and across the High Plains.
Colorado as we know it came together in pieces. The northern portion came to into U.S. control as part of the Louisiana Purchase in 1803. But the U.S. claim to the southern portion of Colorado conflicted with Spain's claim to the same. Long-story-short, Mexico ultimately relinquished the the rest of Colorado at the end of the Mexican-American War in 1848.
The Territory of Colorado was admitted to the Union on August 1, 1876. The 38th state has since been known as “The Centennial State” because its inception occurred 100 years after the signing of the Declaration of Independence.