U.S. States and Territories, February 8, 1860 to January 29, 1861
U.S. States and Territories, March 2, 1861 to August 1, 1861
Astor House, a Territorial Meeting Place
The Territory of Colorado (1861–76) was the predecessor to the state of Colorado , created on February 28, 1861. The territory was formed in response to the secession crisis as well as a massive influx of white immigrants during the Colorado Gold Rush . It was organized by an act of the Thirty-...