- XX Corps (ACW)
Two
corps of theUnion Army were called XX Corps during theAmerican Civil War . Though both served in the UnionArmy of the Cumberland , they were distinct units and should be recognized as such.McCook's Corps
The first XX Corps, under the command of
Alexander M. McCook , was organized in the aftermath of theBattle of Stones River in January 1863 from what had been the XIV Corps, or right wing of the army, at that battle. It was so identified with its commander that it was generally referred to by other soldiers and even officers as "McCook's corps".The corps took part in a skirmish with Bragg's rearguard at Liberty Gap, Tennessee, during the
Tullahoma Campaign in June 1863. It fought its only major battle under this designation at Chickamauga, where it suffered horrendous casualties in the two days of fighting. The corps took heavy casualties, and it (along withThomas L. Crittenden 's XXI Corps), became consolidated into the new IV Corps (Cumberland). McCook, blamed in large part for the failure at Chickamauga, was relieved of command.Hooker's corps
After the
Battle of Gettysburg , with the armies of the east engaged in stalemate (and a large portion ofRobert E. Lee 'sArmy of Northern Virginia , underJames Longstreet , was serving withBraxton Bragg in Tennessee), Washington dispatchedJoseph Hooker , discredited after his defeat at theBattle of Chancellorsville the previous May, with the XI and XII Corps of theArmy of the Potomac to try to relieve Bragg's siege of Chattanooga. The command played a decisive role in theBattle of Wauhatchie , which opened up the "Cracker Line" to the besieged Union army, and seizedLookout 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 theArmy of the Tennessee . Units from XI and XII Corps were combined in each division. The corps fought valiantly throughout theAtlanta Campaign . AfterJames B. McPherson was killed in theBattle 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 commandedXI Corps (ACW) at Chancellorsville, where it had been routed duringStonewall Jackson 's famed flank march) for his part in the defeat of theArmy of the Potomac , resigned. He was replaced first byAlpheus S. Williams , and thenHenry W. Slocum , both formerXII Corps commanders . Its troops were the first to enter Atlanta after its surrender on September 1st, and later went with Sherman'sArmy of Georgia during hisMarch to the Sea . Williams commanded it from then until theCarolinas Campaign (Slocum having been promoted to army command in the mean time).Joseph Mower assumed command late in the war, reducing Williams to division command once again. 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 ofJoseph E. Johnston 's counterattack. It took part in theGrand Review and was disbanded in June 1865.Command History
*
Alexander M. McCook , 9 Jan 1863-9 Oct 1863
*Joseph Hooker , 14 Apr 1864-28 July 1864
*Alpheus S. Williams , 28 July 1864-27 Aug 1864
*Henry W. Slocum , 27 Aug 1864-11 Nov 1864
*Alpheus S. Williams, 11 Nov 1864-2 Apr 1865
*Joseph A. Mower , 2 Apr 1865-4 June 1865External links
* [http://www.civilwararchive.com/CORPS/20thmcc.htm (McCook's) XX Corps history]
* [http://www.civilwararchive.com/CORPS/20thhook.htm (Hooker's) XX Corps history]
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