After his attacks on May 10, 1864, Grant used May 11 as a planning day. Impressed by the initial success of Upton’s charge on May 10, 1864, Grant decided to use Upton’s tactics of a swift attack along a narrow front, by troops with unloaded rifles, on a much larger scale. Hancocks II corps was to attack the mule shoe salient using Upton’s tactics, while Burnside launched a supporting attack on the Mule Shoe from the east and Wright attacked the Mule Shoe from the west, while Wright launched decoy attacks on the Laurel Hill sector of the Confederate lines west of the Mule Shoe.
Attack preparations showed a complete break down in elementary staff work. Hancock’s corps was completely ignorant of the configuration of the Confederate position they were to attack, the obstacles in their way, or indeed the basic nature of the ground to be covered. Hancock had his attack columns assemble in torrential rain. The attack was to begin at 4:00 AM. Hancock wisely delayed the attack until 4:35 AM, fearing that his men could not find the Confederate position, let alone attack it, in the rainy dark.
Now luck began to shine on the Union. The rain stopped and dawn broke with a mist to conceal the Union attack. Unbeknownst to the Union attackers, the Confederate division holding the section of the Mule Shoe they were going to attack, had been denuded of its artillery due to a false report received by Lee that the Union army was going to withdraw to Fredericksburg. If this occurred, Lee wanted his artillery to be withdrawn and readied for an attacking that he planned to make on the withdrawing Federals. Confederate Major General Allegheny Johnson, commanding the target division of the Union assault, became fearful of a forthcoming attack and appealed to his corps commander Lieutenant General Ewell for the return of his artillery. Ewell granted the request at 3:30 AM, too late for the artillery to be put back into place before the start of Hancock’s assault.
Hancock’s 15,000 men attacking on a half mile front crashed into the Mule Shoe and overran Johnson’s division. The rain had made useless much of the Confederate and Union gunpowder and the fighting was grim hand to hand combat. Hancock’s men, fighting on such a narrow front, quickly lost all unit cohesion and became an armed mob, wading through the mud to battle the Confederates. General Lee swiftly sent reinforcements to attempt to plug the breakthrough made by Hancock.
Grant sent in Warren and Wright’s attacks at 6:30 AM. Wright’s attack on the western side of the Mule Shoe produced the bloodiest fighting of the day, which the troops quickly named the Bloody Angle. Rain began to pour again at 8:00 AM, and the troops fought over entrenchments made slippery with mud and blood. Warren’s attack on the Laurel Hill sector was a fiasco, the Union troops having made attacks there many times before and were convinced that no breakthrough was possible. No Confederate troops were diverted from the fighting at the Mule Shoe by this feeble decoy attack.
Burnside’s corps was involved throughout the day in attacking the east side of the Mule Shoe, the fierce fighting ending in stalemate by 2:00 PM.
Confederate engineers busied themselves throughout the day to build a new line of entrenchments at the base of the Mule Shoe.
By 4:00 AM on May 13, 1864 the new line was completed and the Confederates withdrew to their new line. Only this brought the fight to an end after almost 24 hours of some of the most intense combat experienced in the Civil War. Union casualties were about 9,000 and Confederate casualties were 8,000, which included 3000 Confederates taken prisoner at the start of Hancock’s attack. The result of the fighting was a barren Union victory which had taken the Mule Shoe but failed to break the Confederate line. However, once again Grant could swiftly replace his losses while the Confederates were beginning to rob the cradle and the grave to maintain their ranks.