The Trans-Mississippi Department was an administrative subdivision of the Confederate States of America west of the Mississippi, consisting of Texas, Arkansas, Missouri, Indian Territories recognized by the CSA, and parts of Western Louisiana.
The Confederate Trans-Mississippi Department was formed May 26, 1862, to include Missouri, Arkansas, Texas, Indian Territory (now Oklahoma), and Louisiana west of the Mississippi River. It absorbed the Trans-Mississippi District (Department Number Two), which had been organized January 10, 1862, to include that part of Louisiana north of the Red River, the Indian Territory, and the states of Missouri and Arkansas, except for the country east of St. Francis County, Arkansas, to Scott County, Missouri. The combined department had its headquarters at Shreveport, Louisiana, and Marshall, Texas.
- Maj. Gen. Earl Van Dorn (January 10, 1862 – May 23, 1862, District part of Department Number Two)
- Brig. Gen. Paul O. Hébert (May 26, 1862 – June 20, 1862)
- Maj. Gen. John B. Magruder (assigned June 20, 1862, but did not accept)
- Maj. Gen. Thomas C. Hindman (June 20, 1862 – July 16, 1862)
- Maj. Gen. Theophilus H. Holmes (July 30, 1862 – February 9, 1863)
- Lt. Gen. Edmund Kirby Smith (March 7, 1863 – April 19, 1865)
- Lt. Gen. Simon Bolivar Buckner (April 19, 1865 – April 22, 1865)
- General Edmund Kirby Smith (April 22, 1865 – May 26, 1865)