23,000 Casualties in 12 Hours — The Battle of Antietam (1862)

23,000 casualties. Roughly 12 hours. One of the most devastating days in American history. On September 17, 1862, Union and Confederate forces collided near the small town of Sharpsburg, Maryland, in the Battle of Antietam - the bloodiest single day of combat in American military history. Robert E. Lee had taken the Army of Northern Virginia across the Potomac and into Maryland. Waiting for him was George B. McClellan and the Union Army of the Potomac. What followed was a day of extraordinary violence. From the brutal fighting in The Cornfield, to the slaughter at Bloody Lane, to the desperate struggle for Burnside's Bridge, thousands of soldiers were killed, wounded, captured or reported missing as both armies fought for control of the battlefield. By late afternoon, Lee's army was under enormous pressure. Then, just as the Confederate right appeared close to breaking, A. P. Hill's division arrived after a punishing march from Harpers Ferry and struck Burnside's advancing Union troops. By nightfall, roughly 23,000 men had become casualties. But Antietam's importance went far beyond the battlefield. Lee's first invasion of the North had been stopped. Five days later, President Abraham Lincoln issued the preliminary Emancipation Proclamation, transforming the political and moral dimensions of the Civil War. This documentary tells the story of America's bloodiest day - from Robert E. Lee's Maryland Campaign and the discovery of Special Order 191, through the fighting at the Cornfield, Dunker Church, West Woods, Sunken Road and Burnside's Bridge, to the extraordinary consequences that followed. Gettysburg would come later. So would Pickett's Charge. But no other single day of battle in American military history would produce more casualties. This was Antietam. America's Bloodiest Day.