George B. McClellan’s short marches stood in stark contrast to his plans for September 12. Armed with information of the Confederate abandonment of Frederick, he ordered his troops to converge closer to the hub city of central Maryland. Jesse Reno’s Ninth Corps in the lead sparred across the Monocacy River with Wade Hampton’s cavalry and occupied Frederick by nightfall.
As the Federals neared Frederick, John Walker’s, Lafayette McLaws’, and “Stonewall” Jackson’s columns began tightening their grip on Harpers Ferry. Jackson drove the Martinsburg garrison back into Harpers Ferry, and McLaws sealed off the escape routes from the ferry town to the north. Joseph Kershaw’s South Carolinians ascended Elk Ridge and began treading down the spine of the rugged mountain, closing in on Harpers Ferry and the Federal defenses on Maryland Heights. The march was difficult and slow, the mountain a terrible place to fight a battle, as one veteran under Kershaw recollected.
The tough task of dislodging the Federals from their Elk Ridge defenses fell to Joseph Kershaw’s South Carolinians:
We met the enemy’s skirmishers soon after turning to the left on Elk Ridge, and all along the whole distance of five miles we were more or less harassed by them. During the march of the 12th the men had to pull themselves up precipitous inclines by the twigs and undergrowth that lined the mountain side, or hold themselves in position by the trees in front. At night we bivouaced [sic] on the mountain. We could see the fires all along the mountain side and gorges through Pleasant Valley and up on South Mountain…
Lafayette McLaws’ staffer Henry Lord Page King accompanied the Palmetto Staters to the mountain’s crest and wrote in his diary that night of the miserable terrain.
Almost impassable woods rocks–no road–blind path & no path. Maj. B[radley] came up at last about 6 P.M. & found the enemy beyond an abattis. Attacked them quite late by the skirmishers but Gen. K[ershaw] concluded to wait till morning for main attack. Night dark at first–Men had no water since morning, almost famished–little to eat and no fires allowed. Horses destitute. Laid down on the ground and slept, surrounded by troops & hearing groans of wounded men. Wakeful–water came!–2 1/2 miles distant had to be brought.