Department of the West

The Department of the West, later known as the Western Department, was a major command (Department) of the United States Army during the 19th century. It oversaw the military affairs in the country west of the Mississippi River to the borders of California and Oregon.

The Department of the West was created in a reform of army organization nationwide on October 31, 1853, from a consolidation of the existing 6th Military District (headquartered at Jefferson Barracks, Missouri) and 7th Military District (Fort Smith, Arkansas) Departments. It reported directly to the headquarters of the Army in Washington, D.C. In the 1853 reorganization the Department of the Pacific was also created, from consolidation of the 10th (California) and 11th (Oregon) Departments. The Department of the West's headquarters continued at Jefferson Barracks in St. Louis, although it moved briefly to Fort Leavenworth, Kansas, during the Bleeding Kansas skirmishes.

As the Southern states were seceding, just before the American Civil War began, the department was organized to include the country west of the Mississippi River and east of the Rocky Mountains, except for Texas, Utah Territory, and New Mexico Territory, including Missouri, Arkansas, Iowa, Minnesota, Kansas Territory (the state of Kansas after January 29, 1861), Nebraska Territory, Colorado Territory (after February 28, 1861), Dakota Territory (after March 2, 1861), Indian Territory (later the state of Oklahoma), and Louisiana west of the Mississippi River. On June 6, 1861, Missouri was transferred to the Department of the Ohio.

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