American Battlefield Trust’s map of Burnside’s Bridge from the Battle of Antietam on September 17, 1862 from 12pm–1pm
When Walker’s division was moved north to bolster the Confederate defense of the West Woods, only five small brigades under Gen. David R. Jones were left to cover Lee’s right flank. Their position was good, facing open, rolling ground, that was difficult to attack across. Maj. Gen. Ambrose Burnside’s IX Corps was intended to demonstrate against the Confederate right when the main attack further north began. However, McClellan’s orders for Burnside to move forward were not written until 9:00 am and were not received until 10:00 am. Instead of a single headlong assault against the lower bridge, Burnside first attempted to flank the Confederates with a movement south by Brig. Gen. Isaac Rodman’s division. Rodman could not locate a suitable creek crossing until well after noon. By then, two uncoordinated attempts to capture the bridge had failed. Around 1:00 pm, the 51st Pennsylvania and 51st New York finally charged across the bridge. For four hours, about 500 Confederates under Brig. Gen. Robert Toombs held off Burnside’s corps, suffering about 120 casualties.