On September 16, 1862, the opposing armies, in the Eastern Theater of the American Civil War, completed their concentration around Sharpsburg, Maryland – setting the stage for the Battle of Antietam the following day. After Confederate General Robert E. Lee’s invasion of Maryland and the Union victory at South Mountain, on September 14, Lee chose to stand and fight rather than retreat across the Potomac. He selected a defensive position west of Antietam Creek, with the Potomac River at his back and only one viable crossing at Shepherdstown Ford. On the afternoon of September 15, Lee had fewer than 18,000 men on the field. Union Major General George B. McClellan’s Army of the Potomac, numbering over 70,000 effectives, arrived opposite him that evening, but McClellan—convinced Lee commanded 100,000 or more troops—declined an immediate attack. (This was a horrible mistake which would drive the upcoming casualties much higher than an immediate attack would have.)
Fog delayed operations on the morning of the 16th. McClellan spent hours personally reconnoitering Lee’s four-mile crescent-shaped line, which ran from the Potomac River on the north to Antietam Creek on the south. Meanwhile, Major General Thomas “Stonewall” Jackson’s divisions, having captured Harpers Ferry the previous day, completed a forced march and began arriving that afternoon, roughly doubling Lee’s available strength. Major General A.P. Hill’s Light Division remained behind to parole prisoners and would not reach the field until the next afternoon.
By midday, McClellan finalized his plan: a main effort against Lee’s left (northern) flank using Joseph Hooker’s I Corps, supported by Joseph K.F. Mansfield’s XII Corps and Edwin V. Sumner’s II Corps – while Ambrose Burnside’s IX Corps would make a diversionary attack on the Confederate right at the lower bridge (later to be named Burnside Bridge). In the afternoon he ordered Hooker to cross upper Antietam Creek, at the Upper Bridge and Pry’s Ford, to probe and, if possible, turn the enemy left.
Late that afternoon, elements of Brigadier General George Meade’s division, led by Truman Seymour’s brigade, advanced into the East Woods and clashed with Brigadier General John Bell Hood’s Confederate division. The sharp skirmish lasted until dusk, with artillery fire adding to the intensity. Darkness ended the fighting, but picket lines remained so close that soldiers on both sides could hear one another talking. Sporadic firing continued through a rainy night.
The engagement revealed McClellan’s intended axis of attack. Lee, who had briefly considered a northward offensive toward Hagerstown, instead reinforced his left under Jackson and prepared a purely defensive battle. Union troops bivouacked in the North Woods and nearby farms; Confederates occupied positions from Nicodemus Heights through the West Woods, the Cornfield, and south toward Sharpsburg.
The night of September 16 was tense and expectant. Both armies knew a major clash was imminent. McClellan’s caution had allowed Lee to concentrate most of his scattered force, yet the Union still held a substantial numerical advantage. The positioning and limited combat of the 16th transformed what might have been a Union opportunity to destroy Lee’s army piecemeal into the bloodiest single day in American military history on September 17.
The American Civil War would periodically erupt adjacent to bucolic villages – changing life in them for days, months or even years afterwards. This would happen in sleepy Sharpsburg, Maryland in the early autumn of 1862. By September 15, the residents there could see General Robert E. Lee’s Army of Northern Virginia assembling west of Antietam Creek. There was no indication of any impending battle – much less one as sanguinary as was developing. By the afternoon of September 16, with McClellan’s Army of the Potomac arriving there, fear had to be settling over Sharpsburg’s citizens. With George G. Meade’s division advancing into the East Woods, and periodic skirmishes erupting, many residents fled the town. But most would hunker down with blinds pulled and candles extinguished. Unfortunately, for these wary people, they would have a front seat to history in less than 24 hours.
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