The Battle of Dam No. 1 proved a lost opportunity for the Union Army to break the Warwick-Yorktown line and force a Confederate withdrawal toward Richmond. Instead, Major General George McClellan spent another 17 days completing his heavy artillery emplacements, and the Confederates retreated two days before the proposed Union grand barrage on May 5, 1862. Major General “Prince” John Magruder’s troop maneuvers and elaborate defenses on the Warwick-Yorktown line halted the Army of the Potomac for one month. Union engineers then detailed the abandoned Confederate artillery and surveyed the fortifications, and Brigadier General John G. Barnard, chief engineer of the Army of the Potomac, reported that every kind of obstruction the country offered, including abatis, marsh, and inundation, was skillfully used, and that the line was one of the most extensive known in modern times. As a result, the Confederacy gained valuable time to prepare Richmond’s defenses, and today the Warwick-Yorktown line remains one of the best preserved Civil War earthen fortifications in the country.
