At 10:00 a.m., as fighting raged at the Sunken Road, Ninth Corps commander Gen. Ambrose Burnside received orders to begin his attack against the Lower Bridge and the right flank of Lee's army. Recognizing the difficulty of carrying the bridge by a direct frontal attack, Burnside sent Gen. Isaac Rodman with 3,200 soldiers downstream to cross Antietam Creek and outflank Confederate troops on the high bluffs on the west side of the creek. While Rodman's men moved south, smaller attacks were sent against the bridge over the next three hours, and at least three separate assaults were launched, each bringing heavy loss. The first attack began at 10:00 a.m. under the 11th Connecticut Infantry followed by Crook's Brigade, but Col. Crook mistakenly advanced to a point 300 yards upstream and his men were pinned down by Confederate fire. This failed assault showed how confusion, difficult terrain, and Confederate firepower broke down Union attacks. After Crook's attempt, Gen. Nagle's Brigade was ordered forward at 11:00 a.m., but it too was pinned down by well-concealed Confederates. The third and ultimately successful attack was made by Gen. Ferrero's veteran brigade, as the 51st New York and 51st Pennsylvania Infantry Regiments, about 650 men, charged directly toward the bridge. Confederate resistance at first halted them, but with ammunition running low and Rodman's men finally crossing downstream, Toombs' men retreated and Union soldiers captured this crucial Antietam crossing at about 1:00 p.m.
