- January 1863
- Late January 1863
- The Second Army of the Mississippi was an unofficial name that Major John A. McClernand gave to the combined 13th and 15th Army Corps.
- At its largest, the second Army of the Mississippi consisted of 33, 000 Union soldiers.
- The Second Army of the Mississippi easily overran Brigadier General Thomas J. Churchill’s 5,500-man garrison at Fort Hindman during the Battle of Arkansas Post (January 9 – 11, 1863).
- Major general Ulysses S. Grant discontinued the second Army of the Mississippi in late January 1863 by separating the 13th and 15th Army Corps.