The Burnside Bridge, formerly known as the Rohrbach Bridge and Lower Bridge, is a historic bridge over Antietam Creek located on the Antietam National Battlefield, near Sharpsburg, Maryland. Built in 1836 to connect Sharpsburg to Rohrersville, the bridge was manned by 500 Confederate troops of Robert Toombs' command during the September 1862 Battle of Antietam. These troops held back repeated attacks by Ambrose Burnside's Union forces, who ultimately broke through. However, the rebel defense of Burnside Bridge bought enough time for A.P. Hill's division to arrive from Harpers Ferry and fight the Union to a draw; Burnside prudently chose to retreat back across the bridge before he could be trapped.