The Battle of Hanover Court House, also known as the Battle of Slash Church, took place on May 27, 1862, in Hanover County, Virginia, as part of the Peninsula Campaign of the American Civil War.
On May 27, elements of Brig. Gen. Fitz John Porter's V Corps extended north to protect the right flank of Maj. Gen. George B. McClellan's Union Army of the Potomac. Porter's objective was to deal with a Confederate force near Hanover Court House, which threatened the avenue of approach for Union reinforcements that were marching south from Fredericksburg. The smaller Confederate force, under Colonel Lawrence O'Bryan Branch, was defeated at Peake's Crossing after a disorganized fight. The Union victory was moot, however, for the Union reinforcements were recalled to Fredericksburg upon word of Maj. Gen. Nathaniel P. Banks's rout in the Shenandoah Valley at First Winchester.
Confederate General Joseph E. Johnston withdrew his 60,000-man army from the Virginia Peninsula as McClellan's army pursued him and approached the Confederate capital of Richmond. Johnston's defensive line began at the James River at Drewry's Bluff, site of the recent Confederate naval victory, and extended counterclockwise so that his center and left were behind the Chickahominy River, a natural barrier in the spring when it turned the broad plains to the east of Richmond into swamps. Johnston's men burned most of the bridges over the Chickahominy and settled into strong defensive positions north and east of the city. McClellan positioned his 105,000-man army to focus on the northeast sector, for two reasons. First, the Pamunkey River, which ran roughly parallel to the Chickahominy, offered a line of communication that could enable McClellan to get around Johnston's left flank. Second, McClellan anticipated the arrival of the I Corps under Maj. Gen. Irwin McDowell, scheduled to march south from Fredericksburg to reinforce his army, and thus needed to protect their avenue of approach.
The Army of the Potomac pushed slowly up the Pamunkey, establishing supply bases at Eltham's Landing, Cumberland Landing, and White House Landing. White House, the plantation of W.H.F. "Rooney" Lee, son of General Robert E. Lee, became McClellan's base of operations. Using the Richmond and York River Railroad, McClellan could bring his heavy siege artillery to the outskirts of Richmond. He moved slowly and deliberately, reacting to faulty intelligence that led him to believe the Confederates outnumbered him significantly. By the end of May, the army had built bridges across the Chickahominy and was facing Richmond, straddling the river, with one third of the Army south of the river, two thirds north. (This disposition, which made it difficult for one part of the army to reinforce the other quickly, would prove to be a significant problem in the upcoming Battle of Seven Pines).
While skirmishing occurred all along the line between the armies, McClellan heard a rumor from a Virginia civilian that a Confederate force of 17,000 was moving to Hanover Court House, north of Mechanicsville. If this were true, it would threaten the army's right flank and complicate the arrival of McDowell's reinforcements. A Union cavalry reconnaissance adjusted the estimate of the enemy strength to be 6,000, but it was still cause for concern. McClellan ordered his close friend, Maj. Gen. Fitz John Porter, commander of the newly formed V Corps, to deal with the threat.
Porter departed on his mission at 4 a.m. on May 27 with his 1st Division, under Brig. Gen. George W. Morell, the 3rd Brigade of Brig. Gen. George Sykes's 2nd Division, under Colonel Gouverneur K. Warren, and a composite brigade of cavalry and artillery led by Brig. Gen. William H. Emory, altogether about 12,000 men. The Confederate force, which actually numbered about 4,000 men, was led by Col. Lawrence O'Bryan Branch, and included the 18th, 28th, and 38th North Carolina Infantry regiments, and the 45th Georgia Infantry. They had departed from Gordonsville to guard the Virginia Central Railroad, taking up position at Peake's Crossing, 4 miles southwest of the courthouse, near Slash Church. Another Confederate brigade was stationed 10 miles north at Hanover Junction.
Porter's men approached Peake's Crossing in a driving rain. At about noon on May 27, his lead element, the 25th New York Infantry, encountered Col. James H. Lane's 28th North Carolina on a reconnaissance patrol at the farm owned by Dr. Thomas H. Kinney. The New Yorkers, along with the 1st U.S. Sharpshooters, skirmished briskly with the Confederates until Porter's main body arrived, driving the outnumbered Rebels up the road in the direction of the courthouse. Porter set out in pursuit with most of his force, leaving three regiments (the 2nd Maine, the 44th New York, and the damaged 25th New York), under the command of Brig. Gen. John H. Martindale, to guard the New Bridge and Hanover Court House Roads intersection, a mile to the west of Kinney's farm. This movement exposed the rear of Porter's command to attack by the bulk of Branch's force, which Porter had mistakenly assumed was at Hanover Court House.
Branch also made a poor assumption—that Porter's force was significantly smaller than it turned out to be—and attacked. Col. Charles C. Lee led his own regiment, the 37th North Carolina, along with the 18th North Carolina and two cannons from Latham's Battery. An initial assault by the 18th was repulsed, but when the 37th joined in, Martindale's force was almost destroyed by the heavy fire. The 44th New York suffered 25% casualties and its battle flag received 44 bullet holes.
When messengers reached Porter with news of the engagement, he quickly dispatched the 9th Massachusetts and 62nd Pennsylvania regiments back to the Kinney Farm. The Confederate line broke under the weight of thousands of new troops and they retreated back through Peake's Crossing to Ashland.
General McClellan claimed that Hanover Court House was yet another "glorious victory over superior numbers" and judged that it was "one of the handsomest things of the war." However, the reality of the outcome was that superior (Union) numbers won the day in a disorganized fight, characterized by misjudgments on both sides. The right flank of the Union army remained secure, although technically the Confederates at Peake's Crossing had not intended to threaten it. And McDowell's Corps did not need its roads kept clear because it never arrived—the defeat of Union forces at the First Battle of Winchester by Stonewall Jackson in the Shenandoah Valley caused the Lincoln administration to recall McDowell to Fredericksburg. The estimates of Union casualties vary, from 355 (62 killed, 233 wounded, 70 captured) to 397. The Confederates left 200 dead on the field and 730 were captured by Porter's cavalry.