Battle of Antietam
1862 CE · Maryland, USA
The Battle of Antietam was fought in 1862 CE in Maryland, USA between United States (Union) vs the Confederate States; tactically inconclusive but a strategic Union victory that ended Lee's first invasion of the North.
Battle of Antietam: quick facts
- Date
- 1862 CE
- Location
- Maryland, USA
- Belligerents
- United States (Union) vs the Confederate States
- Commanders
- George B. McClellan vs Robert E. Lee
- Result
- tactically inconclusive but a strategic Union victory that ended Lee's first invasion of the North.
- Casualties
- about 22,700 killed, wounded or missing, the bloodiest single day in American history
- Era
- 🦅 American Wars
- Quiz difficulty
- medium
What happened at the Battle of Antietam?
Fought on September 17, 1862, Antietam was the bloodiest single day in American military history with nearly 23,000 casualties. Union General McClellan intercepted Lee's invasion of Maryland and fought the Confederates to a tactical draw, though Lee was forced to withdraw back to Virginia. The strategic Union victory gave President Lincoln the political cover to issue the Emancipation Proclamation, transforming the war into a fight against slavery.
Did you know?
A copy of Lee's battle orders for Antietam was found wrapped around three cigars by Union soldiers in a field. This 'Lost Order' gave McClellan advance knowledge of Lee's divided army.
Sources and further reading
- Battle of Antietam on Wikipedia for the full account, historiography and primary sources.
- How BattleGuess compiles and checks battle facts: see the About page.
Entry last reviewed 26 September 2026.