American Battlefield Trust’s map of the evening fighting at Fox's and Turner's Gap at the Battle of South Mountain on September 14, 1862.
Only an undersize Confederate force commanded by Confederate Maj. Gen. D. H. Hill protected Turner’s and Fox’s Gaps. Early on September 14, Brig. Gen. Jacob D. Cox’s division of the Union IX Corps launched an attack against Brig. Gen. Samuel Garland’s Tarheel brigade at Fox’s Gap. Cox’s Ohioans overran Garland’s North Carolinians, driving the Southerners from behind a stone wall and mortally wounding Garland. With Fox’s Gap now clear, Cox awaited reinforcements to further his gains.
Meanwhile, at Turner’s Gap, Maj. Gen. Joseph Hooker’s Union I Corps had arrived on the field. Hooker and his men faced the Confederate brigades of Brig. Gen. George B. Anderson and Col. Alfred Colquitt. The Confederate's defended the pass while blocking the National Road. Hooker and Maj. Gen. Ambrose E. Burnside launched a coordinated assault. Union divisions made a relentless charge on the northern end of Turner’s Gap. The Confederate brigades of Robert Rodes, Clement Evans, and Richard Garnett arrived to support the Confederate's already in and around Turner's Gap. With George G. Meade's Pennsylvania Reserve's striking the Confederate left, and a western brigade (soon to be dubbed the Iron Brigade), striking the Confederate right, the Federals broke through the Rebel line, but darkness prevented the capture of Turner’s Gap.
Back at Fox’s Gap, the IX Corps mounted a separate effort to seize control of Turner’s Gap but ran into stiff resistance from the Confederate divisions of John B. Hood and D. H. Hill. Casualties mounted, among them IX Corps commander Maj. Gen. Jesse Reno, who was shot down in almost the same spot as Samuel Garland had been that morning.
Confederate General Robert E. Lee decided to abandon his position along South Mountain before dawn on September 15.