Lee’s plan to drive McClellan away from Richmond was bold and daring, and strategically brilliant. He would bring Jackson’s forces down from the valley quickly and secretly to turn McClellan’s right flank at Mechanicsville. At the same time Gen. A. P. Hill’s division would cross the Chickahominy at Meadow Bridge, turn east and clear the Federal forces from Mechanicsville, thereby opening the Mechanicsville Turnpike bridge for D. H. Hill and Longstreet’s troops to cross. Then, in echelon, the four divisions would sweep down the north side of the Chickahominy, annihilate Porter’s corps, capture the supply base at White House, then turn and destroy the rest of the Union army. With Jackson’s forces and other reinforcements from farther south, Lee would have about 90,000 men, the largest army he would ever command in the field.
To protect Richmond, he planned to leave about one-third of his army, under Generals John B. Magruder and Benjamin Huger, in the entrenchments around the city to hold back the main part of McClellan’s force, about 70,000 men, from marching into the Confederate Capital. If this force started to withdraw, then Magruder and Huger would attack.
Lee apparently believed that McClellan would try to retreat to his base at White House, or failing that, would retire back down the peninsula. He assured Jefferson Davis that “any advance of the enemy toward Richmond will be prevented by vigorously following his rear and crippling and arresting his progress.” The strategy was just about perfect, but, unfortunately for Lee, the tactics were not.
On the morning of June 25 the Seven Days began with the advance of Hooker’s division along the Williamsburg road at Oak Grove, preparatory to a general advance McClellan planned for the next day. But Hooker ran into strong opposition from Huger’s troops, and when McClellan received intelligence of Jackson’s approach, Hooker was ordered back. McClellan wired Washington: “I incline to think that Jackson will attack my right and rear.” He had delayed too long—the next day Lee wrested the initiative from him.
Beaver Dam Creek (Ellerson’s Mill)
According to Lee’s plan, Jackson was to march from Ashland on June 25 and encamp that night just west of the Central Railroad. At 3 a.m. on the 26th he was to advance and envelop Porter’s right flank at Beaver Dam Creek. Then, wrote Lee, “A. P. Hill was to cross the Chickahominy at Meadow Bridge when Jackson’s advance beyond that point should be known and move directly upon Mechanicsville.”
Confederate attack at Beaver Dam Creek. From a contemporary sketch.
But from the beginning, unforeseen circumstances upset the operation and timing of this plan. McClellan suspected Jackson’s approach, so the element of surprise was lacking. And when the action of the Union pickets in destroying bridges and felling trees in Jackson’s path, as well as the fatigue of his weary troops, combined to delay him, the all-important time element was lost.
As the day wore on with no word from Jackson, A. P. Hill became impatient and fearful for the success of Lee’s plan. He decided to attack regardless. At 3 that afternoon he crossed the Chickahominy and swept the Union outposts from Mechanicsville, thus clearing the way for D. H. Hill and Longstreet’s troops to cross. Porter withdrew to a prepared position behind Beaver Dam Creek, a mile east of Mechanicsville. This naturally strong position was further fortified by felled trees and the banks of a millrace. Here, atop the high banks of the stream, he placed Gen. George McCall’s division, extending from near the Chickahominy on the south, across Old Church road (now U.S. 360) on the north. Gen. Truman Seymour’s brigade held the left and Gen. John Reynold’s the right, with Gen. George G. Meade’s brigade in reserve. The only approaches to the position were across open fields, commanded by the Federal artillery, and down the steep banks of the stream, covered by the soldiers’ muskets.