There were three organizations known as the Army of Mississippi in the Confederate States Army during the American Civil War. (This name is contrasted against Army of the Mississippi, which was a Union Army named for the Mississippi River, not the state of Mississippi.)
Army of Mississippi (March 1862)
This army, at times known by the names Army of the West or Army of the Mississippi (the latter particularly at Shiloh), was one of the most important in the Western theater, with battles from Shiloh to Perryville. It was organized on March 5, 1862, and portions of the Army of Pensacola were added on March 13. It was consolidated with the Army of Central Kentucky and the Army of Louisiana on March 29. On November 20, 1862, it was renamed the Army of Tennessee.
- Gen. P.G.T. Beauregard: March 5, 1862 (assumed March 17, 1862) to March 29, 1862
- Gen. Albert Sidney Johnston: March 29, 1862 to April 6, 1862; Shiloh
- Gen. P.G.T. Beauregard: April 6, 1862 to May 6, 1862
- Gen. Braxton Bragg: May 6, 1862 (assumed May 7, 1862) to July 5, 1862
- Maj. Gen. William J. Hardee (temp): July 5, 1862 to August 15, 1862
- Gen. Braxton Bragg: August 15, 1862 to September 28, 1862
- Lt. Gen. Leonidas Polk (temp): September 28, 1862 to November 7, 1862; Perryville
- Gen. Braxton Bragg: November 7, 1862 to November 20, 1862
Army of Mississippi (December 1862)
The second army was also referred to as the Army of Vicksburg. It was organized December 7, 1862, from troops in the Department of Mississippi and East Louisiana, including the short-lived Confederate Army of West Tennessee. Its sole function was to defend Vicksburg, Mississippi, and it ceased to exist when it surrendered to Maj. Gen. Ulysses S. Grant on July 4, 1863.
- Lt. Gen. John C. Pemberton: December 7, 1862 to December 9, 1862
- Maj. Gen. Earl Van Dorn (temp): December 9, 1862 to December 17, 1862
- Lt. Gen. John C. Pemberton: December 17, 1862 to July 4, 1863; Vicksburg Campaign
Army of Mississippi (1863–64)
The third army was retitled III Corps, Army of Tennessee, around May 4, 1864, but it continued to use the former name.
- Lt. Gen. William J. Hardee: July 30, 1863 to October 23, 1863
- Lt. Gen. Leonidas Polk: October 23, 1863 to June 14, 1864; Atlanta Campaign
- Maj. Gen. William W. Loring: June 14, 1864 to June 23, 1864