Sibley’s small army conducted a successful campaign up New Mexico’s Rio Grande Valley. Meanwhile, reinforcements from neighboring Colorado Territory moved south to prevent the Texans from seizing Fort Union, the primary garrison along the Santa Fe Trail.

First Colorado Volunteer Infantry, New Mexico volunteers, and other soldiers encountered Texas forces near Glorieta Pass on March 26, 1862, east of Santa Fe. This high point on the southern end of the Sangre de Cristo Mountains crossed the route to Fort Union.

ompany of Colorado mounted infantry charged the Confederates west of the Glorieta summit in snowy Apache Canyon. This advance halted at dusk without a clear victory. The armies engaged again on March 28. Day’s end seemed to bring about victory for the Southerners.

Confederate fortunes changed dramatically when a force of Colorado and New Mexico troops destroyed the Confederate supply train near Johnson’s Ranch. Unable to continue the advance northwards, Sibley and his troops retreated back toward Santa Fe and ultimately back to Texas.

The Battle of Glorieta Pass, sometimes called the "Gettysburg of the West," ended Confederate hopes of establishing access to mineral resources in Colorado. Colorado and New Mexico territorial troops had effectively preserved the Union in the west. The proud heritage of these citizen-soldiers lives on in today's Colorado and New Mexico Army National Guards.