What Was the Single Bloodiest Day in American History?

One of the most significant events in American history is the Civil War, which lasted from 1861 to 1865. It was a time of great turmoil and bloodshed, with countless lives lost as a result of the conflict. However, there was one day during this period that stands out as the single bloodiest day in American history – the Battle of Antietam.

The Battle of Antietam

The Battle of Antietam took place on September 17, 1862, near Sharpsburg, Maryland. It was fought between Confederate General Robert E. Lee’s Army of Northern Virginia and Union General George B. McClellan’s Army of the Potomac. The battle lasted for over 12 hours and resulted in a staggering number of casualties on both sides.

The Numbers

The exact number of casualties at Antietam is still debated by historians, but it is believed that there were around 23,000 casualties in total. This includes both Union and Confederate soldiers who were killed, wounded or missing in action.

To put this into perspective, this single day saw more American casualties than any other day before or since. In fact, more Americans died at Antietam than on D-Day during World War II or on September 11th.

  • Union: approximately 12,410
  • Confederate: approximately 10,700

The Impact

Despite the high number of casualties suffered by both sides during the Battle of Antietam, it is considered a strategic victory for the Union army. This is because it forced General Lee to retreat back into Virginia and prevented him from invading Maryland again.

Moreover, following the battle President Abraham Lincoln issued his Emancipation Proclamation which declared all slaves within rebel-held territory to be free. This proclamation changed the tone of the war and made it clear that the Union was not only fighting to preserve the Union, but also to end slavery.

The Legacy

The Battle of Antietam had a lasting impact on American history. It was a turning point in the Civil War and played a pivotal role in shaping the country’s future. The staggering loss of life on both sides served as a reminder of the high cost of war, and helped to galvanize public support for the Union cause.

Today, Antietam is preserved as Antietam National Battlefield and is open to visitors who wish to learn more about this important event in American history.


The Battle of Antietam was undoubtedly one of the bloodiest days in American history. The sheer number of casualties suffered by both sides is staggering and serves as a reminder of the cost of war.

However, it also played a crucial role in shaping America’s future by helping to bring an end to slavery and preserving the Union. Today, it is remembered as one of the most significant events in American history, and its legacy continues to be felt today.