Henry Cole entered the service as Captain of Company A, on August 10, 1861. He was then promoted to Major, August 1, 1862; Lieutenant- Colonel; March 5, 1864; Colonel, April 20, 1864. During the siege of Harper's Ferry, Va., on September, 1862, the commanding officer of the beleaguered garrison desiring to communicate with General McClellan and the Army of the Potomac, sent for Major Cole, and advised him of his wishes in the premises. Major Cole volunteered his services, passed through the enemy's lines, delivered the dispatch in person, and received the thanks of General McClellan. Colonel Cole mustered out of service on June 28, 1865.