II Corps (Union Army)

II Corps
Army of the Potomac II Corpes badge (trefoil)
Active	1862–1865
Country	United States
Branch	Union Army
Type	Army Corps
Size	Corps
Part of	Army of the Potomac
Motto(s)	"Clubs are trumps"
Engagements	American Civil War
Commanders
Notable commanders	Edwin Vose Sumner Darius N. Couch Winfield Scott Hancock Gouverneur K. Warren Andrew A. Humphreys
Insignia
1st Division
2nd Division
3rd Division

There were five corps in the Union Army designated as II Corps (Second Army Corps) during the American Civil War. These formations were the Army of the Cumberland II Corps commanded by Thomas L. Crittenden from October 24, 1862, to November 5, 1862, later renumbered XX Corps; the Army of the Mississippi II corps led by William T. Sherman from January 4, 1863, to January 12, 1863, renumbered XV Corps; Army of the Ohio II Corps commanded by Thomas L. Crittenden from September 29, 1862, to October 24, 1862, transferred to Army of the Cumberland; Army of Virginia II Corps led by Nathaniel P. Banks from June 26, 1862, to September 4, 1862, and Alpheus S. Williams from September 4, 1862, to September 12, 1862, renumbered XII Corps; and the Army of the Potomac II Corps from March 13, 1862, to June 28, 1865. Of these five, the one most widely known was the Army of the Potomac formation, the subject of this article.

The II Corps was prominent by reason of its longer and continuous service, larger organization, hardest fighting, and greatest number of casualties. Within its ranks was the regiment that sustained the largest percentage of loss in any one action; the regiment that sustained the greatest numerical loss in any one action; and the regiment that sustained the greatest numerical loss during its term of service. Of the one hundred regiments in the Union Army that lost the most men in battle, thirty-five of them belonged to the II Corps. The II Corps also fought in nearly every battle in the main eastern theater, from the 1862 Peninsula Campaign to the Confederate surrender at Appomattox Court House.

The corps was organized under General Orders No. 101, March 21, 1862, which assigned Brigadier General Edwin Vose Sumner to its command, and Brigadier Generals Israel B. Richardson, John Sedgwick, and Louis Blenker to the command of its divisions. Within three weeks of its organization the corps moved with George B. McClellan's Army of the Potomac on the Peninsula Campaign, except for Blenker's division, which was withdrawn on March 31 from McClellan's command, and ordered to reinforce John C. Frémont's army in western Virginia. Blenker's division never rejoined the corps. The remaining two divisions numbered 21,500 men, of whom 18,000 were present for duty.