The Battle of Antietam, also known as the Battle of Sharpsburg, changed the course of the American Civil War. Fought on September 17, 1862, General George B. McClellan’s Army of the Potomac launched a series of assaults against General Robert E. Lee’s Army of Northern Virginia along Antietam Creek near the Maryland village of Sharpsburg. The soldiers in both armies believed that the destiny of their respective nations rested on the outcome of this battle and fought as if there would be no tomorrow. For many men, there was no tomorrow. The two sides combined suffered an estimated 23,000 casualties, making this horrifying fight the bloodiest single day in American history. Most on both sides expected the battle to resume on the 18th. Despite being heavily outnumbered, Lee stayed in position, but McClellan did not renew the attack. That night the Confederate commander ordered his troops back to Virginia, effectively ending Lee’s first invasion of the North. Although the Battle of Antietam ended in a tactical draw, it emerged as a strategic Union victory, frustrating Confederate hopes for European recognition, raising Northern morale, and precipitating President Abraham Lincoln’s Emancipation Proclamation.

This Moment In History: Battle of Antietam

This Is Why We Stand