Department of the Pacific was created January 15, 1861, during the American Civil War. The District of Southern California was established on September 25, 1861.
Colonel George Wright, October 4, 1861 - October 14, 1861
Colonel James H. Carleton, October 14, 1861 - November 18, 1861 (Carlton was relieved from command November 18, 1861 and resumed command February 5, 1862.)
Sept. 14, 1861. Col. George Wright, U. S. 9th Infantry Regiment, assigned to command all troops serving in Southern California.
Sept. 25, 1861. The District of Southern California created, uniting the counties of San Luis Obispo, Buena Vista, Tulare, Santa Barbara, Los Angeles, San Bernardino, and San Diego. Col. George Wright was assigned to its command.
Oct. 5, 1861. Expedition from San Bernardino to the Temecula Ranch and Oak Grove, California.
Oct. 4, 1861. Col. George Wright, U. S. 9th Infantry Regiment, assumes command of the District of Southern California.
Oct. 14, 1861. Col. George Wright, U. S. 9th Infantry Regiment, transfers command of District of Southern California to Col. James H. Carleton, First California Infantry.
Nov. 18, 1861. Col. James H. Carleton, First California Infantry, relieved from command of the District of Southern California.
May 15, 1862. Expedition from California to Arizona and New Mexico, organized as the Column from California, Col. James H. Carleton, First California Infantry, commanding. Col. James H. Carleton relinquishes command of the District of Southern California.
May 17, 1862. Col. George W. Bowie, Fifth California Infantry, assumes command of the District of Southern California.
Sept. 5, 1862. Maj. David Fergusson, First California Cavalry, relieved from command of the District of Western Arizona. Maj. Theodore A. Coult, Fifth California Infantry, assigned to command of the District of Western Arizona. Col. Joseph R. West, First California Infantry, assumes command of the District of Arizona.
1863
Feb. 7, 1863. Lieut. Col. Harvey Lee, Fourth California Infantry, assumes command of the District of Southern California.
April 10, 1863. Col. Ferris Forman, Fourth California Infantry, assumes command of the District of Southern California.
May 19, 1863. Lieut. Col. James F. Curtis, Fourth California Infantry, assigned to command the District of Southern California, relieving Col. Ferris Forman.
July 1, 1864. Maj. Gen. Irvin McDowell, U. S. Army, assumes command of the Department of the Pacific. Brig. Gen. George Wright, U. S. Army, assigned to command the District of California.
1865
July 27, 1865. The Military Division of the Pacific replaced the Department of the Pacific and consisted of the Departments of California and the Columbia. Maj. Gen. Henry W. Halleck, U. S. Army, was assigned to command the Military Division of the Pacific. The District of Southern California was absorbed into the newly created Department of California, consisting of the States of California and Nevada and the Territories of New Mexico and Arizona. Maj. Gen. Irvin McDowell, U. S. Army, was assigned to command the Department of California.