Antietam Battle Detail
On September 16, Maj. Gen. George B. McClellan confronted Robert E. Lee’s Army of Northern Virginia at Sharpsburg, Maryland. At dawn on September 17, Hooker’s corps mounted a powerful assault on Lee’s left flank that began the single bloodiest day in American military history.
Attacks and counterattacks swept across Miller’s cornfield and fighting swirled around the Dunker Church. Union assaults against the Sunken Road eventually pierced the Confederate center, but the Federal advantage was not followed up.
Late in the day, Ambrose Burnside’s corps finally got into action, crossing the stone bridge over Antietam Creek and rolling up the Confederate right.
At a crucial moment, A.P. Hill’s division arrived from Harpers Ferry and counterattacked, driving back Burnside and saving the day.
Although outnumbered two-to-one, Lee committed his entire force, while McClellan sent in less than three-quarters of his army, enabling Lee to fight the Federals to a standstill.
During the night, both armies consolidated their lines. In spite of crippling casualties, Lee continued to skirmish with McClellan throughout the 18th, while removing his wounded south of the river. McClellan did not renew the assaults.
After dark, Lee ordered the battered Army of Northern Virginia to withdraw across the Potomac into the Shenandoah Valley.
The Battle of Antietam was fought between the United States of America and the Confederate States of America on September 17, 1862, during the American Civil War.
- Also Known As: The Battle of Antietam is also called the “Battle of Sharpsburg.”
- Date Started: The Battle of Antietam started on Wednesday, September 17, 1862.
- Date Ended: The fighting ended on September 17, 1862.
- Location: The battle took place near the town of Sharpsburg, Maryland, and Antietam Creek.
- Who Won: The battle was a tactical draw, but a strategic victory for the United States of America.
- Civil War Campaign: The Battle of Antietam was part of the Maryland Campaign.
This painting depicts Union soldiers marching into battle at Antietam. Image Source: Library of Congress.
- More Americans died on September 17, 1862, than on any other day in the nation’s military history.
- Clara Barton cared for wounded soldiers at the Battle of Antietam.
- The Battle of Antietam was the first major battle of the American Civil War to be fought on Northern soil.
- Photographer Alexander Gardner took the first photos of dead soldiers on an American battlefield after the Battle of Antietam.
- Three Union generals were mortally wounded during the Battle of Antietam: Major General Joseph Mansfield, Major General Israel Richardson, and Brigadier General Isaac Rodman.
- Three Confederate generals were mortally wounded during the Battle of Antietam: Brigadier General William Starke, Brigadier General George Anderson, and Brigadier General Lawrence O. Branch.
- The Battle of Antietam has two names because the Federals frequently named battles for creeks or rivers that played a role in the fighting, while Confederates used the names of nearby towns or cities.
- General Lee’s battle plans at Antietam were known in advance. Two Union soldiers (Corporal Barton W. Mitchell and First Sergeant John M. Bloss of the 27th Indiana Volunteer Infantry) discovered a mislaid copy of Lee’s detailed battle plans – Special Order 191 – wrapped around three cigars.
- Technically, the Battle of Antietam was a slight tactical victory for the Union because Robert E. Lee withdrew his army from the battle first. More realistically, the battle was a tactical draw, as both armies suffered heavy casualties and neither was a clear victor.
- Strategically, the Battle of Antietam was a Union victory because it forced Robert E. Lee to end his Maryland Campaign and withdraw back to Virginia.
Commanders and Forces Involved
Principal Union Generals
- Major General George B. McClellan
Principal Confederate Generals
- General Robert E. Lee
Union Forces Engaged
- Army of the Potomac
Confederate Forces Engaged
- Army of Northern Virginia
Casualties and Statistics
Number of Union Soldiers Engaged
- Roughly 60,000.
Number of Confederate Soldiers Engaged
- Roughly 35,000.
- 12,401 (2,108 killed, 9,540 wounded, and 753 missing)
- 10,316 casualties (1,546 killed, 7,752 wounded, and 1,018 missing)
Results of the Battle of Antietam
- The outcome of the battle was a tactical draw on the field, but a strategic victory for the Union.
- President Lincoln and Union General-in-Chief Henry Halleck were so upset that General McClellan did not pursue Lee’s army during its retreat into Virginia after the battle that Lincoln relieved McClellan of his command on November 7, 1862.
- President Lincoln used the Union’s strategic victory at Antietam as an opportunity to issue the Emancipation Proclamation on September 22, 1862.
Timeline of the Battle of Antietam
This list shows the main battles and events that took place before and after the Battle of Antietam, and how it fits into the chronological order of the Maryland Campaign.