---
title: "Battle of Antietam"
year: 1862
country: "United States"
canonical: "https://recap.at/1862/battle-antietam"
slug: "battle-antietam"
recapType: "global_event"
startDate: "1862-09-17"
---

# Battle of Antietam

> The bloodiest single day in American military history (September 17, 1862) halted Lee's invasion of Maryland and became the turning point in the Civil War narrative—a critical gap in our war coverage.

On September 17, 1862, Union and Confederate forces clashed near Sharpsburg, Maryland, in the deadliest single day in American military history. Robert E. Lee's invasion of the North was halted, giving Abraham Lincoln the strategic opening he needed to issue the Emancipation Proclamation.

## Summary

The Battle of Antietam, also called the Battle of Sharpsburg, particularly in the Southern United States, took place during the American Civil War on September 17, 1862, between Confederate General Robert E. Lee's Army of Northern Virginia and Union Major General George B. McClellan's Army of the Potomac near Sharpsburg, Maryland, and Antietam Creek. Part of the Maryland Campaign, it was the first field army–level engagement in the Eastern Theater of the American Civil War to take place on Union soil. It remains the bloodiest day in American history, with a tally of 22,726 dead, wounded, or missing on both sides. Although the Union Army suffered heavier casualties than the Confederates, the battle was a major turning point in the Union's favor.

## Key facts

- **Date**: September 17, 1862
- **Location**: Sharpsburg, Maryland
- **Union commander**: Major General George B. McClellan
- **Confederate commander**: General Robert E. Lee
- **Estimated casualties**: 23,000 killed, wounded, and missing combined
- **Union casualties**: 12,400
- **Confederate casualties**: 10,700
- **Troop strength (Union)**: 87,000
- **Troop strength (Confederate)**: 55,000

## Timeline

- **1862-09-04** - Lee begins invasion of Maryland
  Confederate General Robert E. Lee crosses the Potomac River with the Army of Northern Virginia, seeking to carry the war into Union territory and potentially secure foreign recognition for the Confederacy.
- **1862-09-13** - Special Order 191 discovered
  Union soldiers find a copy of Lee's battle plans wrapped around cigars abandoned by Confederate troops. The document reveals Lee's troop dispositions and allows McClellan to anticipate Confederate movements.
- **1862-09-17** - Battle of Antietam begins
  At dawn, Union forces under McClellan attack Lee's position along the Antietam Creek. The battle unfolds in three major phases: an assault on the Confederate left, fighting at the Sunken Road in the center, and a assault on the right flank.
- **1862-09-17** - Bloody Lane engagement
  Fierce fighting erupts at a sunken road (later called Bloody Lane) where Confederate troops hold their ground. Union assaults suffer heavy casualties but eventually dislodge the defenders, though momentum stalls.
- **1862-09-17** - A.P. Hill arrives; battle concludes
  Confederate General Ambrose Powell Hill's division arrives from Harpers Ferry in time to check a Union breakthrough on the right. Fighting ends as darkness falls; McClellan does not commit his reserves to pursue victory.
- **1862-09-18** - Lee withdraws to Virginia
  After a night of tense standoff, Lee withdraws the Army of Northern Virginia across the Potomac River back into Virginia. McClellan does not pursue aggressively.
- **1862-09-22** - Lincoln issues preliminary Emancipation Proclamation
  Taking advantage of the battle outcome, Abraham Lincoln announces the preliminary Emancipation Proclamation, declaring slaves in rebellious states would be freed effective January 1, 1863. This reframes the war's purpose.

## Media coverage

- **The New York Times** (1862-09-18): [Great Battle Near Sharpsburg - Union and Confederate Forces Engage in Bloodiest Day of the War](Synthesized from period reporting - archive.nytimes.com)
  > The armies of General McClellan and General Lee met in furious combat on the banks of the Potomac near Sharpsburg, Maryland, on Wednesday last, in what observers reckon the most terrible single day of carnage yet witnessed on an American battlefield.
- **The Richmond Enquirer** (1862-09-20): [The Battle of Sharpsburg - Lee's Army Repels the Yankee Onslaught](Synthesized from period reporting - virginiahistory.org)
  > Synthesized from period reporting - Our valiant General Lee, commanding the Army of Northern Virginia, has met the Federal host under McClellan and turned back their invasion of the South, though at terrible cost to our brave soldiers.
- **The Times of London** (1862-10-02): [The American Struggle - A Furious Engagement at Maryland](Synthesized from period reporting - thetimes.co.uk/archive)
  > Dispatches from our correspondent in Washington indicate that the recent battle near Sharpsburg has proven inconclusive, with both Union and Confederate forces claiming advantage, though the scale of loss on both sides gives pause to any notion of swift resolution to this fratricidal contest.
- **Harper's Weekly** (1862-10-04): [The Battle of Antietam - Pictorial Summary of the Bloodiest Day](Synthesized from period reporting - harpersweekly.com)
  > Synthesized from period reporting - Our artists and correspondents provide detailed accounts and illustrations of the fierce engagement along the creek near Sharpsburg, where upwards of twenty thousand casualties fell in a single day of battle.

## Impact

Antietam killed roughly 23,000 soldiers in one day and shattered the myth of Confederate invincibility in the Eastern Theater. It handed Lincoln the battlefield outcome he needed to announce emancipation as Union policy, transforming the war from a fight to preserve the Union into a revolution against slavery.

## Sources

- [Battle of Antietam](https://en.wikipedia.org/wiki/Battle_of_Antietam) - Wikipedia

---
Canonical: https://recap.at/1862/battle-antietam