This Happened — September 17: The American Civil War's Bloodiest Day

Updated September 17, 2024 at 10:50 a.m.

The Battle of Antietam was a significant engagement fought during the American Civil War which took place on this day in 1862, near Sharpsburg, Maryland, along the banks of the Antietam Creek. It was one of the bloodiest single-day battles in American history.

Get On This Day In History delivered straight to your inbox ✉️ each day! Sign up here.

Who were the main participants in the Battle of Antietam?

The battle was fought between the Confederate Army of Northern Virginia, commanded by General Robert E. Lee, and the Union Army of the Potomac, commanded by Major General George B. McClellan.

What were the key objectives of the Battle of Antietam for both sides?

For the Confederate forces under General Lee, the battle was part of his Maryland Campaign, an attempt to bring the war to Northern soil, gain European recognition for the Confederacy, and alleviate pressure on Virginia. For the Union forces under General McClellan, it was an opportunity to halt Lee’s advance, protect Washington, D.C., and potentially deal a decisive blow to the Confederacy.

What were the casualties of the Battle of Antietam?

The Battle of Antietam resulted in a staggering number of casualties. The Union and Confederate armies suffered approximately 23,000 casualties combined, with around 3,650 soldiers killed and about 17,300 wounded. This single-day battle had a profound impact on both sides and highlighted the brutal nature of the Civil War.

How did the Battle of Antietam impact the Civil War?

The Battle of Antietam gave the Union a morale boost and demonstrated that Confederate forces could be repelled on Northern soil. The Emancipation Proclamation, issued shortly after the battle, shifted the war’s narrative toward abolition. The battle also discouraged European powers from recognizing the Confederacy, which was important for the Union’s diplomatic efforts. Additionally, the battle provided President Abraham Lincoln with a window of opportunity to issue the preliminary Emancipation Proclamation, which changed the war’s focus by highlighting the Union’s commitment to ending slavery.

All rights reserved