The Department of California was an administrative department of the United States Army. The Department was created in 1858, replacing the original Department of the Pacific, and it was ended by the reorganizations of the Henry L. Stimson Plan implemented in February 1913. As with the preceding organization, headquarters were in San Francisco.[1] Its creation was authorized by General Orders, No. 10, of the War Department, Adjutant-General's Office, September 13, 1858.
As first established, the department covered all territory within the latter-day state borders of Arizona, Nevada, California, and a sizable square of southwestern Oregon representing the Rogue River District and Umpqua District.