South Mountain: The Battle That Unlocked Antietam
Near Harpers Ferry, Maryland
On September fourteenth, eighteen sixty-two, three days before the bloodiest single day in American history, a battle was fought in the mountain passes above this valley that made Antietam possible.
Robert E. Lee's Confederate Army had crossed the Potomac and was moving through western Maryland on the first Southern invasion of the North. Lee intended to resupply in Pennsylvania, win a decisive victory on Union soil, and force a negotiated peace before Europe would intervene. What he did not expect was that a copy of his actual operational orders, Special Orders One Ninety-One, would be found wrapped around three cigars in a field near Frederick by a Union soldier and rushed to General George McClellan.
With Lee's plans in hand, McClellan pushed his Army of the Potomac west toward South Mountain, whose gaps represented the only practical passage through the Blue Ridge. Confederate General D. H. Hill had orders to hold those passes until Lee could concentrate his scattered force. Hill threw his men across three gaps, Fox's, Turner's, and Crampton's, and a desperate fight developed across the ridge through the afternoon.
The numbers favored the Union heavily. Roughly twenty-eight thousand Federal soldiers engaged against fewer than eighteen thousand Confederates. But the mountain passes narrowed the front and allowed smaller forces to hold far longer than on open ground. Hill's men fought from behind stone walls and tree lines, slowing one Union corps after another.
By nightfall the passes had fallen. Among the dead was Major General Jesse Reno, commander of the Union Ninth Corps, shot at Fox's Gap in almost the same position where Confederate General Samuel Garland had died that morning. Total casualties reached about five thousand between both sides.
Lee pulled his men back and concentrated at the little town of Sharpsburg near Antietam Creek. Three days later the armies met there in twelve hours of fighting that killed and wounded more than twenty-two thousand men. The road to Antietam ran through these gaps.
