There were seven major Indian Wars fought in Colorado between 1864 and 1879.
The Colorado region was part of the Viceroyalty of New Spain from 1535 to 1682, New France from 1682 to 1762, Kingdom of Spain from 1762 to 1800, French First Republic 1800 to 1803, and part of the United States of America 1803–present (boundaries were disputed by Spain).
The southern portion of Colorado was considered by Spain as part of its northern territories. Large portions of Colorado were subsequently under the administrative control of Mexico from 1800 to 1835, and the Republic of Texas from 1836 to 1846.
Full administrative control of Colorado was established on February 2, 1848 with the signing of the Treaty of Guadalupe Hidalgo which ended the Mexican–American War.
Colorado Indian Wars
|Nov 29,1864||Sand Creek Massacre near Eads, Colorado||United States of America vs Cheyenne & Arapaho||187
Reports of Native Americans killed in action vary from 70 to 163.
|Jan 7, 1865||Battle of Julesburg near Julesburg, Co||United States of America & civilian volunteers vs Cheyenne, Arapaho, & Lakota Sioux||14|
|Jan 14, 1865||Battle of Beecher Island in Yuma County, Colorado||United States of America vs Arapaho, Cheyenne & Lakota Sioux||41
Reports of Native Americans killed in action vary from 9 to 32.
|July 11, 1869||Battle of Summit Springs near Sterling, Colorado||United States of America vs Arapaho, Cheyenne & Sioux||35|
|Sept 29, 1879||Meeker Massacre at White River Indian Agency, near modern Meeker, Colorado||White River Ute vs United States civilians||11|
|Sept 29 – October 25, 1879||Battle of Milk Creek near Meeker, CO||White River Ute vs United States of America||32-50
13 US soldiers killed in the action; Native Americans killed varies from 19-37.