XX Corps (Union Army) - Hooker's Corps

Hooker's Corps

After the Battle of Gettysburg, with the armies of the east engaged in stalemate (and a large portion of Robert E. Lee's Army of Northern Virginia, under James Longstreet, was serving with Braxton Bragg in Tennessee), Washington dispatched Joseph Hooker, discredited after his defeat at the Battle of Chancellorsville the previous May, with the XI and XII Corps of the Army of the Potomac to try to relieve Bragg's siege of Chattanooga. The command played a decisive role in the Battle of Wauhatchie, which opened up the "Cracker Line" to the besieged Union army, and seized Lookout Mountain in the famed "Battle Above The Clouds" during the early stages of the Battle of Chattanooga.

On April 4, 1864, just before the onset of the Atlanta Campaign, William T. Sherman, authorized the consolidation of XI and XII Corps as XX Corps, under Hooker's command, to serve in the Army of the Cumberland. Units from XI and XII Corps were combined in each division. The corps fought valiantly throughout the Atlanta Campaign. After James B. McPherson was killed in the Battle of Atlanta on July 22, Oliver O. Howard was made commander of the army. Hooker, partially because Howard was junior to him and partially because he blamed Howard (who had commanded XI Corps (ACW) at Chancellorsville, where it had been routed during Stonewall Jackson's famed flank march) for his part in the defeat of the Army of the Potomac, resigned. He was replaced first by Alpheus S. Williams, and then Henry W. Slocum, both former XII Corps commanders . Its troops were the first to enter Atlanta after its surrender on September 1, and later went with Sherman's Army of Georgia during his March to the Sea. Williams commanded it from then until the Carolinas Campaign (Slocum having been promoted to army command in the mean time). It played a major part in the seizure of Savannah in December and was actively engaged throughout the Carolinas Campaign, particularly at Bentonville, where it absorbed the main blow of Joseph E. Johnston's counterattack. Because fighting at Bentonville had not destroyed Johnston's army, Sherman replaced Williams with the more petulant Joseph A. Mower. It took part in the Grand Review and was disbanded in June 1865.