Union Organisations: Western Territories and Pacific Coast Theatre
Go to Pacific Coast Theatre / Trans-Mississippi, Northwest, and Frontier Theatres / Western Theatre / Gulf Coast Theatre / Eastern Theatre / Capital and North-Eastern Theatre / Atlantic Coast Theatre for detailed summaries.
This theatre broadly covers the state of California, and the Arizona Territory, Colorado Territory, Dakota Territory, Nevada Territory, New Mexico Territory, Oregon Territory, Utah Territory, and adjacent operational regions.
At the outbreak of war, the Department of Utah, Department of New Mexico, and the Department of the Pacific were responsible for the area. In July 1861, the Department of Utah was discontinued, and its territory was brought under the Department of the Pacific. Utah transferred to the Department of the Missouri in February 1865 and was never again reconstituted as a military Department.
The Department of New Mexico was also discontinued in July 1861 and its territory was transferred briefly to the Western Department. The Western Department proved to be torn between its westward and eastward-facing responsibilities, so the Department of New Mexico was re-established in November 1861, after the dissolution of the Western Department.
The Department of the Pacific and the revived Department of New Mexico, and their Districts, shared military authority in the Far Western theatre. The District of Colorado was attached only as an administrative convenience from September to October 1862 during the recreation of the Department of the Missouri.
Both the Department of the Pacific and the Department of New Mexico were discontinued in the post-war reorganisation of 27 June 1865. The territory of the former was divided into the Department of California and the Department of the Columbia, and the territory of the latter was divided between the Department of the Pacific and the Department of the Missouri.
This is an alphabetical Index of each Organisation by Level and then by name
Details of each specific organisation can be found in the Introduction to Union Military Organisations – Types -by searching for the Level and then the Name of the Organisation
Military Division of the Pacific
Department of California #1
Department of California #2
Department of the Columbia
Department of New Mexico #1
Department of New Mexico #2
Department of Oregon
Department of the Pacific
Department of Utah
District of Arizona #1
District of Arizona #2
District of California
District of Southern California
District of Colorado
District of Colorado Territory #1
District of Colorado Territory #2
District of Dakota
District of the Humboldt, California
Central and Northern District of New Mexico
Southern District of New Mexico
District of Oregon
District of Utah
American Civil War High Command 