Jackson recrossed the Potomac on the 11th, at Light’s Ford, ordered A. P. Hill’s division by the turnpike to Martinsburg, his own and Ewell’s northwest to North Mountain Depot to intercept troops that might retreat in that direction from Martinsburg. General White, commanding the Union troops, abandoned Martinsburg the night of the 11th, having timely advice of Jackson’s movements, and retreated to Harper’s Ferry. On the 12th, Jackson’s troops came together at Martinsburg, found some stores of bacon and bread rations, and marched on the 13th for Harper’s Ferry, where he found the Union troops in battle array along Bolivar Heights.
I marched across South Mountain at Turner’s Pass, and bivouacked near its western base. General Lee ordered my move continued to Hagerstown. The plans of the Confederates, as blocked out, anticipated the surrender of Harper’s Ferry on Friday, the 12th, or Saturday, the 13th, at latest. The change of my position from Boonsborough to Hagerstown further misled our cavalry commander and the commanders of the divisions at Boonsborough and Harper’s Ferry into a feeling of security that there could be no threatening by the army from Washington.
D. H. Hill’s division crossed by Turner’s Gap and halted near Boonsborough. McLaws took the left-hand road, marched through Burkittsville, and halted for the night at the east base of the mountain, near Crampton’s and Brownsville Passes.
Near Crampton’s Pass on the west the mountain unfolds into two parallel ridges, the eastern, the general range of South Mountain, the western, Elk Ridge, opening out Pleasant Valley, about three miles from crest to crest.
Crampton’s is the northern of the two passes, and about eight miles south of Turner’s. One mile south of Crampton is the Brownsville Pass, and four miles from that the river pass, which cuts in between the Blue Ridge of Virginia and South Mountain of Maryland. Through the river pass the Baltimore and Ohio Railway, the canal, and the Fredericktown turnpike reach out to the west, and at the pass is the little town of Riverton. Between Riverton and Harper’s Ferry was the hamlet Sandy Hook, occupied by about fifteen hundred Federal troops. Two roads wind through Pleasant Valley, one close under South Mountain, the other hugging the foot-hills of Elk Ridge,—the latter rugged, little used.
Harper’s Ferry, against which Lee’s new movement was directed, nestles at the confluence of the Potomac and Shenandoah Rivers, on the Virginia side, under the towering cliffs of Maryland or Cumberland Heights. At Harper’s Ferry the river cuts in so close under Maryland Heights that they stand almost perpendicularly over it. The crowded space between the heights and the river, filled by the railway, canal, and turnpike, was made by blastings from the southern extremities of Maryland Heights. Under the precipice the railroad bridge crosses the Potomac, and a pontoon bridge was laid a few yards above it.
McLaws marched over into Pleasant Valley on the 11th, through Brownsville Pass, near which and over Elk Ridge a road passes through Solomon’s Gap of Elk Ridge. From the top of this gap is a rugged way along the ridge leading down to its southern projections and limits, by which infantry only could find foothold. That southern point is called Maryland Heights. Two brigades—Kershaw’s and Barksdale’s—under General Kershaw were ordered to ascend Elk Ridge, march along its summit, driving off opposition, and capture the enemy’s position on the heights. General Semmes was left near the pass, over which the troops had marched with his own and Mahone’s brigades, the latter under Colonel Parham with orders to send a brigade to the top of Solomon’s Gap to cover Kershaw’s rear. General Wright, of Anderson’s division, was ordered with his brigade and two pieces of artillery along the crest ridge of South Mountain to its projection over Riverton. General Cobb was ordered with his brigade along the base of Elk Ridge, to be abreast of Kershaw’s column. With the balance of his command, General McLaws moved down the Valley by the South Mountain road, connecting his march, by signal, with General Kershaw’s. Kershaw soon met a strong force of skirmishers, which was steadily pushed back till night. General Wright, without serious opposition, reached the end of the mountain, when R. H. Anderson sent another brigade—Pryor’s—to occupy Weverton. On the 13th, Kershaw renewed his fight against very strong positions, forced his way across two abatis, along a rugged plateau, dropping off on both sides, in rocky cliffs of forty or fifty feet, encountered breastworks of logs and boulders, struggled in a severe fight, captured the position, the enemy’s signal station, and at four P.M. gained possession of the entire hold. Cobb’s brigade was advanced, and took possession of Sandy Hook without serious opposition. The column near South Mountain was advanced to complete the grasp against the enemy at Harper’s Ferry. Up to this hour General McLaws had heard nothing direct from Generals Jackson and Walker, though from the direction of the former sounds of artillery reached him, and later a courier told that Jackson thought his leading division would approach at two o’clock that afternoon. During the day heavy cannonading was heard towards the east and northeast, and rumors reached McLaws of the advance of the enemy from Frederick, but the signal-parties and cavalry failed to discover movements, so the firing was not credited as of significance. The morning of the 14th was occupied in cutting a road for his artillery up to the point overlooking Harper’s Ferry, and at two P.M. Captains Read and Carlton had their best guns in position over the town. But during these progressions the Confederates on other fields had been called to more serious work.
General McClellan, moving his columns out from the vicinity of Washington City on the 5th, made slow and very cautious marches to save fatigue of his men and at the same time cover the capital against unforeseen contingency; so slow and cautious was the march that he only covered forty or fifty miles in seven days. On the 12th his head-quarters were at Urbana, where he received the following telegram from President Lincoln:
“Governor Curtin telegraphs me, ‘I have advices that Jackson is crossing the Potomac at Williamsport, and probably the whole rebel army will be drawn from Maryland.’”
The President added,—