Chapter 24
July 4, 1863
The centre of the battle between the Army of Northern Virginia and the Army of the Potomac was located west of Cashtown near the entrance to the South Mountain gap with the road leading to Chambersburg. On the Union Army side, Hancock's and Sykes' corps, together just over 21,000 men, advanced, while the gap was defended by Pender's and Heth's divisions of A. P. Hill's corps, nearly 13,000 infantry. As this was the only place within the battle line where the terrain was almost unwooded and very open, the rebels under Lee had also assembled the majority of their artillery there. In addition to the two battalions from Hill's Artillery Reserve under Colonel Reuben Walker, a detached battalion each of Longstreet's and Ewell's corps were also on site. This gave the Confederates a decisive advantage over Hancock's and Sykes' corps artillery.
As soon as the first elements of the northern infantry entered the gap, they were taken under heavy gunfire. Romeyn Ayres' United States Regulars as well as John Caldwell's and parts of John Gibbon's division advanced boldly and steadfastly under good flank protection, while projectiles blew big holes in their ranks. They were adequately received by Confederate brigades under Abner Perrin, Alfred Scales, Johnston Pettigrew and Joseph Davis.
Heavy hand-to-hand combat broke out between Patrick Kelly's Irish Brigade and the 26th North Carolina under Colonel Henry Burgwyn, after both units had initially shot each other to pieces from a distance of less than one hundred yards and Kelly had personally ordered the survivors of his small brigade to attack, taking a regimental flag from the hands of a dying colour guard. The North Carolinians fought where they stood and repulsed the attack. It is remarkable, however, that despite the deep penetration of the Irish into the rebel lines, not a single flag was lost during the retreat.
Alexander Webb fell at the head of his men as the brigade attacked under triple huzzah and were blasted to smithereens by a battery with double canister.
The most significant loss on the Confederate side was brigade commander John Brockenbrough, who was hit in the neck by a stray minie ball and bled to death within minutes.
While the defenders held their ground, Hancock and Sykes were still in good shape and ready for further action when sudden events on their right drastically changed the nature of the conflict.
Maj. Gen. Winfield Scott Hancock, USA