What Was the Bloodiest Single Day of Fighting in American History?

On September 17, 1862, the United States experienced the bloodiest single day of fighting in its history. This day is known as the Battle of Antietam and it was fought between the Confederate Army of Northern Virginia and the Union Army of the Potomac. The battle took place near Sharpsburg, Maryland and resulted in over 23,000 casualties.

The Lead-Up to Antietam

The Civil War had been raging for over a year when General Robert E. Lee decided to invade Maryland. His goal was to bring the war to northern soil and hopefully gain support from European countries that were considering recognizing the Confederacy as a legitimate nation. However, Lee’s invasion plans were discovered by Union General George B. McClellan, who began to pursue him.

The two armies clashed on September 17th at Antietam Creek. It was a fierce battle that lasted from dawn until dusk.

The Battle Begins

At dawn, Union troops began to attack Confederate positions along Antietam Creek. The Confederate soldiers were heavily outnumbered but they held their ground for several hours, inflicting heavy casualties on the Union troops.

As the morning progressed, both sides continued to reinforce their positions with fresh troops. The fighting intensified and both sides suffered massive losses.

The Cornfield

One of the bloodiest parts of the battle was a cornfield that lay between the two armies. The Union troops advanced across it multiple times but were repelled by Confederate fire each time. By noon, nearly 5,500 soldiers had been killed or wounded in the cornfield alone.

Bloody Lane

Another deadly spot was a sunken road known as Bloody Lane. Here, Confederate soldiers had dug in and were able to repel wave after wave of Union attacks. By mid-afternoon, over 5,000 soldiers lay dead or wounded in the lane.

The Aftermath

By the end of the day, both sides had suffered heavy losses. The Union Army had over 12,000 casualties and the Confederate Army had over 10,000. It was a strategic victory for the Union as they were able to stop Lee’s invasion plans and push him back into Virginia.


The Battle of Antietam was a brutal and bloody affair that lasted for just one day but left a lasting impact on American history. It remains the deadliest single day of fighting in American history and serves as a reminder of the cost of war.