Battle of Antietam
September 17, 1862
During the early-morning hours of the Battle of Antietam, 27,000 Union and Confederate infantrymen fought amidst 6-foot stalks of corn for control of this field.
In early fall 1862, General Robert E. Lee and his Army of Northern Virginia were riding a wave of recent military success, and the Confederates were feeling invincible. The time was right, Lee and President Davis agreed, for the Southern army’s first invasion into the North. The goals of the Maryland Campaign were both practical and political. First and foremost, Virginia's farms had been stripped bare and Lee's 55,000 men needed food. At the same time, by bringing the fight to the North, the Confederates would further damage the Union’s already sagging morale just before the November elections. Southern politicians also hoped that if Lee won a significant battle in the North, the French and British would be encouraged to officially recognize the Confederacy, and possibly offer assistance in the war.
On the Union side, things were less optimistic. The war was going badly, and President Lincoln was losing support from both the people and the politicians. He needed a major military victory to turn the tide, especially one on Northern soil. Maj. General George McClellan and his 75,000-man Army of the Potomac were sent to intercept Lee, and fortune seemed with them when two soldiers from the 27th Indiana Volunteer Infantry discovered a mislaid copy of Lee's detailed battle plans. Special Order 191, found wrapped around three cigars on September 13th, gave McClellan the exact locations of Lee's divided army. Concerned it was a trap, and always slow to move troops, McClellan waited nearly 18 hours before acting on the intelligence. The opportunity to divide and conquer Lee's army was lost.
On September 15th, the army under General Lee's immediate command consisted of no more than 18,000 men. Lee was aware that Federal infantry was on the way, so he deployed his troops in a defensive position along a low ridge behind Antietam Creek, near the town of Sharpsburg. It was an effective, but not impregnable position. The narrow creek did not provide much of a barrier in front and the Confederate army's rear was blocked by the Potomac River, with only a single crossing point nearby should retreat be necessary. It was, however, ground of Lee’s choosing, and reinforcements were on the way.
The first two Union divisions arrived in Sharpsburg on the afternoon of the 15th, and most other troops arrived by evening. The following morning McClellan still had a huge numbers advantage, but believing Lee had as many as 100,000 men, he was again cautious. Finally, on the evening of the 16th, McClellan ordered Maj. General Joseph Hooker's First Corps to cross Antietam Creek and probe the enemy's left flank near the East Woods. The skirmish only served to further signal McClellan's intentions to Lee. As darkness fell, artillery fire continued while McClellan positioned his troops for the next day's attack. In the meantime, Confederate reinforcements had begun to arrive, and the Southerners were fortifying their defensive positions along the 4-mile line.
The Union attack on September 17th unfolded as three separate, mostly uncoordinated fights: First, at dawn, Hooker's corps mounted a powerful assault on Lee's left flank, but were repulsed by Confederate infantry and artillery. Attacks and counterattacks swept across Miller's cornfield and fighting raged around the Dunker Church, but no ground was gained. The second fight within the battle took place at mid-day, when a Union offensive pierced the Confederate center near the Sunken Road. Without a plan, the Federal advantage was not followed up and the Southern line was allowed to reform. In the afternoon, the third stage of the battle began when Union Maj. General Ambrose E. Burnside's corps entered the action, capturing a stone bridge over Antietam Creek and advancing against the Confederate right. At a crucial moment, however, Confederate reinforcements arrived and launched a surprise counterattack, driving Burnside's men back to end the day's fighting.
The armies consolidated their lines during the night, and continued to skirmish the following day, while Lee's battered soldiers began to move south of the Potomac River. Much to Lincoln's dismay, McClellan refused to send his army in pursuit, even though a third of his men were still fresh, having been held out of the fight the previous day. The battle was militarily inconclusive, but because the Confederate troops had withdrawn first, the Union claimed a technical victory. Lincoln was furious at McClellan for his ill-coordinated and poorly executed performance, however the victory gave him the political confidence to announce the Emancipation Proclamation, declaring to the world that the war would end slavery in the United States.
Antietam was the bloodiest single-day battle in American history, with a combined total of 22,717 dead, wounded, captured and missing.