Battle of Beaver Dam Creek - Background and Lee's Plan

Background and Lee's Plan

After the Battle of Seven Pines, on May 31 and June 1, McClellan and the Army of the Potomac sat passively at the outskirts of Richmond for almost a month. Lee, newly appointed commander of the Confederate Army of Northern Virginia, devoted this period to reorganizing his army and preparing a counter-attack. He also sent for reinforcements. Stonewall Jackson arrived on June 25 from the Shenandoah Valley following his successful Valley Campaign. He brought four divisions: his own, now commanded by Brig. Gen. Charles S. Winder, and those of Maj. Gen. Richard S. Ewell, Brig. Gen. William H. C. Whiting, and Maj. Gen. D.H. Hill

The Union Army straddled the rain-swollen Chickahominy River. Four of the Army's five corps were arrayed in a semicircular line south of the river. The V Corps under Brig. Gen. Porter was north of the river near Mechanicsville in an L-shaped line running north-south behind Beaver Dam Creek and southeast along the Chickahominy. Lee moved most of his army north of the Chickahominy to attack the Union north flank. He left only two divisions (under Maj. Gens. Benjamin Huger and John B. Magruder) to face the Union main body. This concentrated about 65,000 troops against 30,000, leaving only 25,000 to protect Richmond against the other 60,000 men of the Union army. It was a risky plan that required careful execution, but Lee knew that he could not win in a battle of attrition or siege against the Union army. The Confederate cavalry under Brig. Gen. J.E.B. Stuart had reconnoitered Porter's right flank (as part of a daring, although militarily pointless, circumnavigation of the entire Union army from June 12 to June 15) and found it vulnerable. McClellan was aware of Jackson's arrival and presence at Ashland Station, but did nothing to reinforce Porter's vulnerable corps north of the river.

Lee's plan called for Jackson to begin the attack on Porter's north flank early on June 26. Maj. Gen. A.P. Hill's Light Division was to advance from Meadow Bridge when he heard Jackson's guns, clear the Union pickets from Mechanicsville, and then move to Beaver Dam Creek. The divisions of Maj. Gens. D.H. Hill and James Longstreet were to pass through Mechanicsville, D.H. Hill to support Jackson and Longstreet to support A.P. Hill. Lee expected Jackson's flanking movement to force Porter to abandon his line behind the creek, and so A. P. Hill and Longstreet would not have to attack Union entrenchments. South of the Chickahominy, Magruder and Huger were to demonstrate, deceiving the four Union corps on their front.