The 4th Maine Volunteer Infantry Regiment was assembled in Rockland, Maine on By May 20, 1861 with Colonel Hiram G. Berry as its commanding officer. He received four Knox County companies, one from Searsport, Winterport, Wiscasset, and Damariscotta, and two from Belfast. In all, 1,085 men, including a regimental band, were mustered. The regiment was mustered out of service July 19, 1864, with the expiration of their term. The veteran volunteers and recruits were transferred to 19th Maine Infantry. Of the 1440 men that served in the regiment during the war 170 men were killed in action or died of wounds received in battle. An additional 443 were wounded, 137 men perished of disease, and 40 men expired in Confederate prisons.