Organized at Worcester, and left the State August 22, 1862. Both Colonel Wild and Lieutenant Colonel Carruth had seen service in the First Massachusetts. After a short stay on Arlington Heights, the regiment was ordered to join McClellan's Army, then on its way to meet Lee in Maryland. It was assigned to Ferrero's (2d) Brigade, Reno's (2d) Division, Ninth Corps. It was engaged at South Mountain, where it won praises from all who saw it in action; Colonel Wild received a serious wound there, resulting in amputation of an arm. Three days later, the regiment fought at Antietam, the casualty list at that battle footing up 48 killed, 160 wounded, and 6 missing; Major Sidney Willard, who was in command, was killed while cheering on his men. The Thirty-fifth accompanied the corps in its western campaigns in Kentucky, at Vicksburg, and at the siege of Knoxville, Tenn. Upon its return to Virginia it was brigaded in the First Brigade of Stevenson's (1st) Division, from which it was subsequently transferred to Potter's (2d) Division. At Poplar Spring Church the regiment, under Lieutenant-Colonel Hudson, lost 6 killed, 19 wounded, and 156 prisoners,--the latter loss occurring not through any fault of the men, nor of the officers. The Thirty-fifth remained on duty before Petersburg, suffering heavy losses in the trenches, and sharing in the triumphant termination of the siege.