 After Hunter's Company A retreated from Tucson and arrived in Mesilla on May 27, 1862, it was organized with two Arizona militia companies, the Arizona Guards of Pinos Altos and the Arizona Rangers of Mesilla, under Herbert's Battalion of Arizona Cavalry under the command of Lt.Colonel Philemon T. Herbert.It served as rearguard to the remnants of the Army of New Mexico as it withdrew from El Paso to San Antonio, in July 1862.