On the night of September 14, 1862 Confederate General Robert E. Lee, realizing that the forces of General George McClellan’s Army of the Potomac were forcing the gaps along South Mountain, quickly directly his scattered Army of Northern Virginia to the defensive high ground along the fields north and west of Sharpsburg.
Historians often wondered why Lee would risk his entire army by posting them with their backs to the Potomac and only a small cross able ford in their rear thus creating inherent risk in the selection of the ground of his choosing.
Lee understood his opponent, McClellan, was a very cautious man and had driven him onto the James River earlier in the year during the Seven Day’s battles and having selected good ground of his own choosing was willing to offer battle on his terms to the Union general not wishing to retire back to Virginia without fighting that battle.
Lee's confidence in the army was very high after a successful summer campaign where he had driven both McClellan and General Pope back into Washington. Now the Union Army was coming on fast after pushing the thin defenses of D.H. Hill out of the South Mountain gaps on the 14th, and heavy skirmishing took place near Sharpsburg on the 16th.
Those same historians, often infamous for their revisionist slant on the battle and war, easily bought the Union story-line that Lee was defeated at Sharpsburg by the fact that he left the field on the 19th, two days after the battle.
President Lincoln desperate for a victory after a summer of failure, quickly declared success for the Union Army (although he scrapped his General) and issued the emancipation proclamation thereby freeing slaves in the Confederacy while at the same time retaining their servitude in the Yankee areas.
Earlier in the year he had freed the slaves in Washington partly due to the hypocritical charges of northern abolitionists against him who saw slave labor in the current construction of the future Capital Building as an odd irony. In fear of losing neutral border States to the Confederacy, Lincoln restricted the order to Confederate States that were under Union control at the time. His motivation was in attempting to create a slave revolt in the CSA. In fact many of these liberated areas, the Union Army conscripted the slaves to build their field works thereby freeing more soldiers for the front lines. Many of the slaves willfully complied but those who wished to return South to their homes were not allowed to do so under orders of execution for leaving their new masters.
General Lee had allowed his soldiers without shoes (no small number) to stay behind in Virginia as he marched into Maryland earlier in the month because he realized the macadamized roads of Maryland would tear his men’s bare feet apart. The soft clay dirt roads of Virginia were easier on his men and those who fell out would be there to reinforce him upon his return to the Old Dominion. By the time the battle of Sharpsburg/Antietam took place, Lee reported scarcely 38,000 arrayed for battle against a foe with nearly triple his numbers. Lee fought his entire army while McClellan Fifth Corps under Porter and the Sixth under Franklin had little work.
The battle of Sharpsburg was in fact three separate battles fought in one day. At dawn Hooker’s First Corps came storming out of the cornfields later supported by Mansfield’s Twelfth Corps and were repulsed by Stonewall Jackson, with the aid of J.B. Hood’s Division as well as an enfilading cannonade under the direction of Jeb Stuart. The combat was a bloody slug fest each side driving the other back over cornfields and woods until the ground was littered with the bodies of thousands of dead and dying men. The fighting here started to wane around 9am after over fours hours of constant bloody struggle. The Confederate line, while batten mauled had held its ground.
The battle shifted to the bloody sunken lane, manned mostly by North Carolinian’s and Georgian’s when it came under heavy assault shortly past 9am. Sumner’s Second Corps, supported by the Mansfield on their right, came on in waves and the Irish Brigade under Meagher got into a flanking position and enfiladed D.H. Hill’s men with deadly salvos of “buck and ball”. The Confederates began to fall back and it appeared the day was won for the Union. Several savage small Confederate counterattacks along with heavy blasts of canister from their field artillery, one of the batteries manned by Longstreet and his staff officers, shocked the blue wave and forced them back. It had been the opinion of the Union general staff that the Confederates under Lee had many more in numbers than were actually present. It was the “Confederate ghost in the woods” that often prevented them from exploiting momentary opportunity as it was presented during battle.
As the battle in the center slowed down to sporadic fire, the third act of the day opened on the Confederate extreme right near Burnside’s Bridge where the Corps under that general attempted to cross the Antietam and flank Lee’s Army with the intentions of severing his escape route to Virginia by taking the Shepardstown Road. The bridge was thinly defended by a brigade of Georgians who had stubbornly resisted the crossing of Burnside’s Ninth Corps. Burnside dispatched nearly half of his command, the Kanawha Division under Scammon and the Third Division under Rodman, 2 miles down river to cross behind the Confederates at Snavely’s ford. During the time he awaited for the later to cross the Antietam, he attacked with his other two Divisions across the bridge and after several failed attempts they succeeded in crossing and finally driving the Confederates back towards Sharpsburg. Just as it appeared that Burnside has turned Lee’s right flank, A.P. Hill arrived on the field with his Light Division, after a forced march up from Harper’s Ferry, and slammed into the left of Burnside. That shock buckled the Union line and forced them back over the Antietam to their starting positions.
The battle of Antietam is a story of missed opportunities and a desperate fight for survival. Throughout the day McClellan’s uncoordinated attacks allowed for General Lee to use his interior lines to fortify his battle line at the next hot spot prior to the assault which he knew was coming- it were as if he had a chair at McClellan’s command post. At any time McClellan could have deployed the remaining forces and swept the field and quite possible won the war that day but he was forever haunted by the “Confederate ghosts in the woods.” The Union pell-mell and disjointed attacks came at a heavy price. The Union lost 12,400 and the Confederates lost 10,300. Nearly 23,000 which is more than Pearl Harbor, D-day and 9-11 combined!
The Confederate General staff was alarmed that Lee would not give up the field after that terrible day and he ordered his men to prepare to receive battle yet again on the 18th but McClellan would have none of it. Both sides exchanged sniper fire on the 18th but no major effort was made by either side that day to attack the other. On the night of the 18th, the Army of Virginia, bloodied but not broken, crossed over the Potomac near Shepardstown and onto Virginian soil.