The Trans-Mississippi Army was a field army of the Confederate States Army in the Trans-Mississippi Theater of the American Civil War. It was the last major Confederate command to surrender, submitting on May 26, 1865, exactly one month after General Johnston had surrendered in the eastern United States.[1]
The Trans-Mississippi Department separated from the Western Department of the Confederate States Army on May 26, 1862. It consisted primarily of the three Confederate states west of the Mississippi (Texas, Louisiana, and Arkansas), the contested state of Missouri, and two Confederate territories - the Indian Territory and Confederate Arizona (roughly corresponding to the present-day states of Oklahoma, New Mexico, and Arizona). The command of the area was given to Major-General T. H. Holmes.[2] It was the operational theater for many quasi-independent forces, including Quantrill's Raiders and the Missouri Bushwhackers.
The Trans-Mississippi Army originally numbered well over 50,000 troops,[3] but fewer than 43,000 were available by the end of the war.[2][4] Major campaigns included Sibley's New Mexico campaign, Banks' Red River campaign, and Price's Missouri campaign. The last battle of the Civil War, the Battle of Palmito Ranch, was fought May 12–13, 1865, by units of the Trans-Mississippi Army.
General E. Kirby Smith, who commanded the Army, surrendered to Union forces on May 26, 1865, although by that point many of his troops had already deserted.[5] The last remaining Trans-Mississippi Army force – and also the last remaining Confederate force – was the 1st Cherokee Mounted Rifles, commanded by Brigadier-General Stand Watie. Watie surrendered on June 23.