The Battle of Apache Pass was fought in 1862 at Apache Pass, Arizona, in the United States, between Apache warriors and the Union volunteers of the California Column as it marched from California to capture Confederate Arizona and to reinforce New Mexico's Union army. It was one of the largest battles between the Americans and the Chiricahua during the Apache Wars. Background The 2500 men of the California Column traveled across the arid Southwest in staggered groups to allow water sources to replenish. In early 1862 Col. James H. Carleton sent units from Fort Yuma to Tucson, Arizona, which had recently been occupied by a Confederate force, Company A, Arizona Rangers. After a small engagement known as the Battle of Picacho Pass just north of Tucson between a detachment of Carleton's cavalry and Confederate pickets, the Union forces advanced on Tucson in three columns. They arrived in Tucson on May 20, forcing the heavily outnumbered Confederate garrison to withdraw to Texas without a fight. After capturing Confederate Arizona's western outpost, Carleton prepared to march east with his main body in July, intending to enter New Mexico through Apache Pass in southeast Arizona. To prepare for the advance of his main force, he sent a column ahead as he had on his march from Yuma to Tucson. The column was led by Capt. Thomas L. Roberts of Company E, 1st California Infantry, accompanied by two 12-pounder mountain howitzers under the command of Sgt. James D. Monihon, a 22-man cavalry escort from Company B, 2nd Regiment California Volunteer Cavalry, led by Capt. John C. Cremony and 21 wagons plus 242 mules and horses. After Roberts reached the San Pedro River, it became necessary to learn whether Dragoon Springs, 28 miles further east, could supply both companies with water or whether they would be forced to separate into smaller detachments. Capt. Roberts led the advance detachment with his infantry company, joined by three wagons, the howitzers and seven of Cremony's best horsemen to serve as scouts and couriers. Capt. Cremony remained behind with 15 cavalrymen and ten of Roberts' infantrymen, including the detachment left as a garrison at the river, where an adobe stage station building provided shelter and a defensive position to guard the remaining wagons and animals. Roberts found the water at Dragoon Springs was enough to support the entire force, and Cremony joined with him the next day. Together they