The Union ships advanced against the Confederate positions on June 17. The 46th Indiana Infantry Regiment was sent ashore to attack the fortifications on land, while two ironclads and two timberclads attacked the fort from the river. During the fighting, a Confederate solid shot struck the ironclad USS Mound City, puncturing one of the ship's steam drums. In what has been referred to as the deadliest shot of the war, scalding steam filled the ship, killing or wounding all but about 25 of the roughly 175 men on the vessel. The 46th Indiana overran the Confederate defenses on land and the position was taken. The supply mission was unable to make it all the way to Curtis's position, and withdrew back down the river due to low water levels. Thereafter, Curtis's army cut loose from their supply line and marched to Helena, Arkansas. A portion of the battlefield is listed on the National Register of Historic Places as the St. Charles Battle Site.
