In the fall of 1862, Governor John Evans began organizing the 3rd Colorado Infantry Regiment. Starting in September companies were organized under direction of the regiment's first commander Colonel William Larimer, and his deputy, Lieutenant Colonel Samuel S. Curtis. The regiment was garrisoned at Camp Weld during its training. During the regiment's formation, there was an understanding that Col. Larimer's command was temporary as the regiment's command was intended for James H. Ford, who was serving with 2nd Colorado Infantry Regiment. However there was fierce competition for recruits in the Colorado territory and Col. Larimer was only able to raise five companies and portions of sixth. In December, Col. Larimer resigned his position in the regiment
In October 1863, the 3rd Colorado Infantry was consolidated with the 2nd Colorado Infantry Regiment and the subsequent formation was re-designated as the 2nd Colorado Cavalry Regiment.
On March 5, 1863, the 3rd Colorado Infantry Regiment departed Camp Weld and marched to Fort Leavenworth, Kansas
The roster of the 3rd Cavalry contains 1309 names.
Dyer, Frederick H. A Compendium of the War of the Rebellion