Department of California

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. 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. 
Commanders.
The Department of California was commanded first by Brevet Brigadier General Newman S. Clarke, Colonel U.S. 6th Infantry Regiment, until his death on October 17, 1860. It was next commanded by Lt. Colonel Benjamin L. Beall, U.S. 1st Dragoon Regiment, who had assumed command, by seniority of rank, on the death of General Clarke, on October 17, 1860. It was merged into the restored Department of the Pacific on January 15, 1861, as the District of California administering the same territories, commanded by Brevet Brigadier General Albert Sidney Johnston from January 15, 1861.
Reduction to District status 1861-1865.
When General Edwin Vose Sumner, relieved General Johnston during March 1861 he continued in command of the Department of California now renamed the District of California. His successor in October 1861, Brigadier General George Wright continued in command of the District even after losing command of the Department of the Pacific, on July 1, 1864, to Gen. Irvin McDowell.
Department again June 1865 - February 1913.
During June 1865, Col. Edward McGarry was ordered to succeed Brigadier General George Wright (who was relocating to his new command of the Department of the Columbia), in command of the District of California until General McDowell could take command of the District which was again raised to Department status once more under the Military Division of the Pacific, now commanded by Major General Henry W. Halleck. The territory encompassed by the new Department of California now consisted of the States of California and Nevada and the District of New Mexico and District of Arizona in the Territories of New Mexico and Arizona. Maj. Gen. Irvin McDowell, U. S. Army, assigned to command the Department of California.
The Department of Arizona was established as part of the Division of the Pacific on April 15, 1870. It consisted of Arizona Territory and California south of a line from the northwest corner of Arizona to Point Conception so as to include most of Southern California.
From December 7, 1871, the one general officer at San Francisco commanded both the Division of the Pacific and the Department of California and the separate staffs were consolidated into one. On July 1, 1878, Division of the Pacific headquarters was relocated from San Francisco to the Presidio of San Francisco.
The Department of Arizona lost Southern California to the Department of California on February 14, 1883, but regained California south of the 35th parallel on December 15, 1886. The Department of California then consisted of California north of the 35th parallel and Nevada.
The Military Division of the Pacific was discontinued on July 3, 1891. Each of the three subordinate departments of Arizona, California, and the Columbia, then reported directly to the War Department. The Department of California, with its headquarters at San Francisco, consisted of California north of the 35th parallel and Nevada.
The Hawaiian Islands were added to the department July 12, 1898. It became the District of Hawaii in 1910 as part of the Department of California.
From 1904 to 1907, the Department of California, as well as the Department of the Columbia, were subordinate to a re-established Division of the Pacific known as Pacific Division. It became independent again after 1907 until they were subordinated to a new Western Division from 1911 to 1913. 
On February 15, 1913 the Department of California, with all the mainland territorial departments, was disbanded for a new organization of the Army. The territory of the former departments of the Columbia and California were now controlled by the Western Department, except for the District of Hawaii that now became the independent Department of Hawaii.