Antietam, Battle of

Antietam, Battle of (1862).The appointment of Gen. Robert E. Lee as commander of the Army of Northern Virginia on 1 June 1862 helped reverse the momentum of the Civil War. Union armies and naval forces had won impressive victories along the South Atlantic and Gulf coasts and the river systems of Tennessee, Mississippi, Louisiana, and Arkansas, overrunning some 50,000 square miles of the Confederacy. In Virginia, Maj. Gen. George B. McClellan's large and well‐equipped Army of the Potomac had advanced westward up the Virginia Peninsula to within six miles of Richmond. The Confederate States of America seemed doomed. But during Lee's first three months in command, he launched a series of counteroffensives. In the Seven Days' battles and the battles of Cedar Mountain and Second Manassas, Southern victories shifted the war in Virginia from the gates of Richmond to the environs of Washington. Hoping to strike a knockout blow that would force the Lincoln administration to sue for peace, Lee decided to invade Maryland.

Great possibilities rode with the Army of Northern Virginia as it began crossing the Potomac River northwest of Washington on 4 September 1862. The most powerful nations in the world, Britain and France, were considering diplomatic recognition of the Confederacy; one more military victory would win that crucial goal. A large faction in the Northern Democratic Party wanted peace negotiations; another Union defeat might enable them to capture the House of Representatives in the fall. President Abraham Lincoln had decided in July to issue a proclamation to free the slaves in Confederate states and was awaiting a Union military victory to announce it.

After the defeat at Second Manassas (Bull Run), Lincoln had merged the Union Army of Virginia into the Army of the Potomac and given McClellan command, ordering him to “destroy the rebel army.” Cautious as always, McClellan probed northward along the Potomac. On 13 September at Frederick, Maryland, he had extraordinary luck: two Union soldiers found a copy of Lee's invasion orders wrapped around some cigars lost by a Confederate staff officer. Lee had divided his army into five parts, sending three under “Stonewall” Jackson to capture the Union garrison at Harpers Ferry, which lay athwart Lee's line of communications with the Shenandoah Valley. If he moved quickly, McClellan could destroy the separated units piecemeal. He did not move quickly. Union attacks did overrun Confederate defenders in the South Mountain gaps west of Frederick on 14 September, but failed to save the 12,000 Union troops at Harpers Ferry, which surrendered to Jackson on 15 September. McClellan's tardiness enabled Lee to reunite most of his army along high ground east of the village of Sharpsburg—his left flank on the Potomac and his right on Antietam Creek. Although he outnumbered Lee by about 80,000 troops to 45,000, McClellan assumed that the enemy outnumbered him.

After deliberate preparations that gave Lee time to unite his army, McClellan attacked at dawn on 17 September. His plan called for a one‐two punch against the Confederate left and right, followed by reserves to exploit whatever breakthrough might occur. The Union attacks were uncoordinated, enabling Lee to shift troops from quiet sectors to threatened points. During the early morning hours, assaults by six Union divisions on Jackson's corps were contained in vicious fighting in locales that became forever famous: the Cornfield, the West Woods, and the Dunkard Church. Meanwhile, the commander on the Union left flank, Maj. Gen. Ambrose Burnside, tried to force his troops across a bridge over the Antietam instead of fording that shallow stream. In the center at midday, two Union divisions broke through Confederate defenses along a sunken farm road known ever after as Bloody Lane, but McClellan failed to exploit this success because he feared Lee's nonexistent reserves. Burnside finally punched across the Antietam in early afternoon and advanced toward Sharpsburg, threatening Lee's rear and his retreat route across the Potomac. But at about 4:00 P.M. Maj. Gen. A. P. Hill's Confederate division arrived after a forced march from Harpers Ferry and hit Burnside's flank, halting the Union advance.

The sun set on the deadliest single day in the Civil War—indeed, in all of American history. Some 6,000 men lay dead or dying, and another 16,000 were wounded. The fighting was not renewed next day, and that night Lee retreated to Virginia. McClellan failed to follow up, but nevertheless claimed a victory. Britain and France did not recognize the Confederacy. Republicans retained control of the House in November. And five days after the battle, Lincoln issued his preliminary Emancipation Proclamation.
[See also Civil War: Military and Diplomatic Course.]

Bibliography

James V. Murfin , The Gleam of Bayonets: The Battle of Antietam and the Maryland Campaign of 1862, 1965.
Stephen W. Sears , Landscape Turned Red: The Battle of Antietam, 1983.
Gary W. Gallagher, ed., Antietam: Essays on the 1862 Maryland Campaign, 1989.

James M. McPherson