division, which had joined us on the 2d, being in advance, and-between September 4 and 7 crossed the Potomac at the fords near Leesburg, and encamped in the vicinity of Fredericktown.
It was decided to cross the potomac east of the Blue Ridge, in order, by threatening Washington and Baltimore, to cause the enemy to with-draw from the south bank, where his presence endangered our communications and the safety of those engaged in the removal of our wounded and the captured property from the late battle-fields. Having accomplished this result, it was proposed to move the army into Western Maryland, establish our communications with Richmond through the Valley of the Shenandoah, and, by threatening Pennsylvania, induce the enemy to follow, and thus draw him from his base of supplies.
It had been supposed that the advance upon Fredericktown would lead to the evacuation of Martinsburg and Harper's Ferry, thus opening the line of communication through the Valley. This not having occurred, it became necessary to dislodge the enemy form those positions before concentrating the army west of the mountains. To accomplish this with the least delay, General Jackson was directed to proceed with his command to Martinsburg, and, after driving the enemy from that place, to move down the south side of the potomac upon Harper's Ferry. General McLaws, with his own and R. H. Anderson's division, was ordered to seize Maryland Heights, on the north side of the Potomac, opposite Harper's Ferry, and Brigadier-General Walker to take possession of Loundoun Heights, on the east side of the Shenandoah, where it unites with the Potomac. These several commands were directed, after reducing Harper's Ferry and clearing the Valley of the enemy, to join the rest of the army at Boonsborough or Hagerstown.
The march of these troops began on the 10th, and at the same time the remainder of Longstreet's command and the division of D. H. Hill crossed the South Mountain and moved toward Boonsborough. General Stuart, with the cavalry, remained east of the mountains, to observe the enemy and retard his advance.
A report having been received that a Federal force was approaching hagerstown from the direction of Chambersburg, Longstreet continued his march to the former place, in order to secure the road leading thence to Williamsport, and also to prevent the removal of stores which were said to be in Hagerstown. He arrived at that place on the 11th, General Hill halting near Boonsborough to prevent the enemy at Garper's Ferry from escaping through Pleasant Valley, and at the same time to support the cavalry. The advance of the Federal Army was so slow at the time we left Fredericktown as to justify the belief that the reduction of Harper's Ferry would be accomplished and our troops concentrated before they would be called upon to meet it. In that event, it had not been intended to oppose its passage through the South Mountains, as it was desired to engage it as far as possible from its base.
General Jackson marched very rapidly, and, crossing the Potomac near Williamsport on the 11th, sent A. P. Hill's division directly to Martinsburg, and disposed the rest of his command to cut off the enemy westward. On his approach, the Federal troops evacuated Martinsburg, retiring to Harper's Ferry on the night of the 11th, and jackson entered the former place on the 12th, capturing some prisoners and abandoned stores.
In the forenoon of the following day his leading division, under General A. P. Hill, came in sight of the enemy strongly intrenched on Bolivar Heights, in rear of Harper's Ferry. Before beginning the attack, General Jackson proceeded to put himself in communication with the
10 R R-VOL XIX, PT I