On September 17, 1862, Robert E. Lee’s Army of Northern Virginia clashed with George B. McClellan’s Army of the Potomac at Sharpsburg, Maryland. This twelve hour battle was the single bloodiest day in American history with 23,000 men killed, wounded or missing.
Union General Ambrose Burnsides ordered the IX Corp to take the lower bridge that spanned Antietam Creek. The Confederate forces were not numerically superior but took positions commanding the heights on the other side of the creek, on the bluffs and in a quarry.
The first assault at 9:00 A.M., by two companies of skirmishers of the 11th Ohio Volunteers was repulsed. Colonel Henry W. Kingsbury led an assault by the 11th Connecticut Volunteers at 10 A.M. In an extended front they moved forward to the rail fence and the stone wall near the South and North sides of the bridge. Captain John Griswold of A company plunged into the swift flowing creek with several men but were met by a volley of small arms fire. He was wounded and made it to the far side of the creek where he died. The remaining men had turned back and the regiment was finally forced to retire under the heavy fire of the well concealed Confederates. Colonel Kingsbury died after being wounded multiple times and the 11th Connecticut Volunteers suffered over 130 casualties, representing one third of their men. Two Mansfield soldiers from Co. K of the 11th Connecticut Volunteers were killed in the battle, William H. Hall and Asa W. Rouse.