Organized at Readville, Mass., recruiting having commenced in December, 1863. Many of the men had served terms of enlistment in other regiments. It left the State March 21, 1864, and, with about 850 men, proceeded to Annapolis, where it was attached to the First Brigade, Stevenson's (1 st) Division, Ninth Corps. In the latter part of April it marched to Alexandria, Va., and thence to the Wilderness. Colonel Griswold was killed in that action, and the casualties, as given in the State reports, were 9 killed, 57 wounded, and 10 missing. At Spotsylvania, May 12th, it lost go killed, 41 wounded, and 1 missing; on the 18th, it also lost there 5 killed, and 40 wounded. In the charge of the Ninth Corps on the works at Petersburg--June 17, 1864 -- the regiment was prominently engaged, its losses amounting to 10 killed, 5 t wounded, and 16 missing; this was its hardest fight. It also sustained serious losses while in the trenches before Petersburg, men being killed or wounded daily for several weeks. At the Mine Explosion it lost 4 killed, 21 wounded, and 25 missing. The Fifty-Sixth was a steady, reliable, fighting regiment; although its losses, numerically, were not extraordinary, yet its percentage of killed was far above the average and entitles it to distinction. The Division was broken up in August, 1864, and the regiment transferred to Potter's (2d) Division.