In the days leading up to the Battle of Antietam, Confederate General Robert E. Lee concentrated his invading army outside Sharpsburg, Maryland. Victorious at Manassas in August, Lee's Army of Northern Virginia hoped to garner new recruits and supplies in Maryland, a slave-holding state that remained in the Union. However, Union General George B. McClellan who closely pursued his rival enjoyed a strategic advantage. A scout had discovered a copy of the Confederate battle plan and the contents of Lee's Special Order Number 191 were well-known to his rival.

At dawn on September 17th, 1862 the hills of Sharpsburg thundered with artillery and musket fire as the Northern and Southern armies struggled for possession of the Miller farm cornfield. For three hours, the battle lines swept back and forth across the field.

By mid-morning, the Confederate line was established along a country lane called Sunken Road. The soldiers crouched behind its high banks, unleashing heavy fire upon advancing Union troops. Eventually, the overwhelming number of Northerners broke the Confederate line. As the Southerners spun to defend their position, the Union troops rained bullets lengthwise down the lane onto them. The road came to be known as Bloody Lane because of the tragic toll of death suffered there.

The Southerners retreated towards Sharpsburg, covered by cannon fire from General Stonewall Jackson's artillery. The Union troops fell back in the face of the cannon fire and failed to pursue the Confederates.

Cautious to a fault, McClellan failed to advance quickly on the Confederates who had reached the town. Eventually, General Ambrose Burnside attacked, but was repelled by the ragged Southerners and newly-arrived troops under Major General A. P. Hill.

By nightfall, Confederates occupied the town of Sharpsburg ending the single bloodiest day in American history. Over 23,000 men were killed, wounded, or missing in action. The next day, Lee began his retreat across the Potomac River.