In March 1862, McClellan opened the Peninsula Campaign by sailing from Alexandria, Virginia, to Fort Monroe. Over the next two months, his army cautiously advanced toward Richmond, but Confederate general Joseph E. Johnston checked him at Seven Pines on May 31–June 1. Lee, assuming command for the wounded Johnston, seized the initiative on June 26 by attacking the Union right flank at Mechanicsville. McClellan retreated southeast toward the protection of the Union Navy on the James River, while Lee aggressively pursued, attacking at Gaines’s Mill, Savage’s Station, and Glendale.
The Union Army of the Potomac arrived at Malvern Hill, a one hundred-foot plateau about one mile north of the James River, on June 30. McClellan briefly inspected the position and then boarded a gunboat, leaving Union general Fitz-John Porter in command. With the army united for the first time that week, Porter wisely took advantage of the terrain. He deployed the infantry in a U–shaped line, with the open side facing the James, supported by approximately thirty-six guns on both the hill’s western and northern slopes. The army’s heavy artillery, including twenty- and thirty-pound Parrott rifles, stood in reserve on the southern end of Malvern Hill. That afternoon an advance Confederate division shelled the Union position from the west with five guns. The concentrated Union guns smothered the Confederate battery and another one in support, forcing the Confederates to abandon two cannon and six limbers (two-wheeled carts that supported the artillery piece). It was a preview of what was to come.
The main portion of Lee’s Army of Northern Virginia arrived the next morning, sensing that McClellan’s troops were beginning to break under the unrelenting pressure. Reconnoitering the Union position, Confederate generals James Longstreet and Thomas J. “Stonewall” Jackson identified positions on the Confederate right and left from which to deliver converging artillery fire. After this bombardment disrupted the Union position, Lee’s infantry would attack. Despite repeated attempts, the Confederates failed to mass their guns because of both poor communication work done by the generals’ staff officers and the Confederate practice of deploying batteries with each brigade rather than with the larger division. Of approximately forty-five Confederate artillery pieces that participated in fighting, only six to eight did so simultaneously on either flank. The massed Union guns pounded the Confederate batteries and drove them from the field, inflicting about a hundred casualties and killing more than seventy horses. Union gunboats also lobbed shells into the Confederate lines.
At around three o’clock in the afternoon, Confederate general Lewis A. Armistead‘s brigade attacked Union skirmishers. The Union gunners directed their fire against him, and his men took cover in a ravine part of the way up Malvern Hill. A garbled report of this “success,” coupled with an erroneous one that Union troops were withdrawing (they were actually moving wagons to escape overshot Confederate artillery), prompted Lee to order a discretionary attack. At 5:30 p.m. Confederate general John B. Magruder launched a series of piecemeal brigade attacks from the right. Confederate general D. H. Hill’s division, hearing the firing, advanced on the left, as did other Confederate units. Union artillery, supported by infantry, broke the Confederate formations, but new ones continued to surge forward. Porter repeatedly committed fresh troops and batteries, ultimately employing 107 cannon, and repelled the disjointed attacks until darkness halted the fighting. Union guns continued to wreak havoc on the Confederate lines until ten o’clock that night.
Confederate casualties at Malvern Hill totaled 5,650, compared with the Union’s 3,007. The following morning, a Union officer reported that the numerous wounded Confederates who littered Malvern Hill “give the field a singular crawling effect.” Porter encouraged McClellan to resume the advance on Richmond, but the ordeal of the Seven Days had mentally defeated him. Instead, McClellan ordered the army to retreat to Harrison’s Landing, where it remained until late August, effectively ending the Peninsula Campaign.