Jackson Expedition

The Jackson Expedition occurred in the aftermath of the surrender of Vicksburg, Mississippi in July 1863. Union Maj. Gen. William T. Sherman led the expedition to clear General Joseph E. Johnston's relief effort from the Vicksburg area.

Background
In the Vicksburg Campaign, one of the intermediate battles was the Battle of Jackson on May 14, 1863, in which Maj. Gen. Ulysses S. Grant's Army of the Tennessee captured the capital city of Jackson, Mississippi, but then evacuated it to move west toward Vicksburg. During the Siege of Vicksburg Johnston had been gathering troops at Jackson, intending to relieve pressure on Lt. Gen. John C. Pemberton's beleaguered garrison. Johnston cautiously advanced his 30,000 soldiers toward the rear of Grant's army surrounding Vicksburg. In response, Grant ordered Sherman to deal with Johnston's threat.

Expedition
By July 1, 1863, Johnston's force was in position along the Big Black River. Sherman used the newly arrived IX Corps to counter this threat. On July 5, the day after the surrender of Vicksburg was made official, Sherman was free to move against Johnston. Johnston hastily withdrew his force across the Big Black River and Champion's Hill battlefields with Sherman in pursuit. Sherman had with him the IX Corps, XV Corps, XIII Corps, and a detachment of the XVI Corps.

Siege of Jackson
On July 10 the Union Army had taken up position around Jackson. The heaviest fighting came on July 11 during an unsuccessful Union attack. Brig. Gen. Jacob G. Lauman ordered a brigade under Col. Isaac C. Pugh to attack the Confederate works manned by Brig. Gen. Daniel W. Adams's brigade. As a result Lauman was relieved of command for failing to properly carry out the orders of his superior Maj. Gen. E.O.C. Ord, which resulted in heavy casualties. Instead of risking entrapment, Johnston chose to evacuate the state capital and withdrew on July 16. Sherman's forces occupied the city the following day.

The capture of the city effectively ended the last threat to Vicksburg.