William J. Ross was a U.S. Army officer of the 21st Infantry and a Quartermaster stationed at the Headquarters, Dept. of Arizona, Prescott, Arizona Territory during the period of the letters.

Collection contains holograph carbons of letters written Sept. 4, 1872 to Jan. 15, 1875 concerning accounting for supplies, clothing, equipment, and payrolls for the posts. Most are transmittal letters for reports which are not included. Includes a name index.