The First Colorado Volunteer Infantry was recruited from the mining camps of the Colorado Territory in the fall of 1861. As the miners assembled at Camp Weld (in modern Denver), Confederate General H. H. Sibley invaded the New Mexico Territory with an army of Texans.
Organized by the territory's first governor, William Gilpin, this infantry regiment began enlistment in August 1861. Nicknamed "Gilpin's Pet Lambs" because of the governor's involvement in their organization, the regiment marched to northern New Mexico in February-March 1862. to the defense of Fort Union, New Mexico. The First Colorado marched 92 miles in just 36 hours and on March 26th and March 28th, 1862, the regiment, with a few regular army troops and two light batteries of artillery, defeated the Confederates in battles at Apache Canyon and Glorieta Pass. The Confederates were forced to retreat back to Texas. There they fought in the battles of Apache Canyon and Pigeon's Ranch (also called the Battle of Glorieta Pass) and at Peralta, New Mexico.
In November 1862, the unit was reorganized along with Companies C and D of the 2nd Colorado Infantry into the 1st Colorado Cavalry. (This was done since the US War Department believed cavalry would be better in protecting the Western trails and for fighting the various Indian tribes.)
The first colonel of the regiment was John P. Slough, replaced in April 1862 by Major John Chivington, later chastised for his role as commander of the 3rd Colorado Cavalry in the November 1864 Sand Creek Massacre. The regiment's first and only lieutenant-colonel was Samuel F. Tappan.
After service in garrisons across the west, the unit was mustered out of service in late 1865.
The Colorado State Archives has custody of the casualty records, clothing issue records, some of the muster rolls, and the morning reports relating to this regiment.
Colonel - John P. Slough
Lieutenant Colonel - Samuel F. Tappan
Major - John Chivington BATTLES:
No rosters for this unit prior to their organization as the 1st Cavalry Regiment have been found. The roster of the 1st Cavalry contains 2645 names.