 Many were former members of the three local Arizona Militia companies from Pinos Altos and Messila.On February 10, 1862 Company A was ordered to occupy Tucson, the largest town in the western Confederate Territory of Arizona.Tucson was located on the Butterfield Overland Mail road, the only one between California and the Rio Grande and Mesilla valleys, and an ideal location for an advanced post to observe and delay the advance of Union forces gathering under Col. James Henry Carleton at Fort Yuma.