George B. McClellan’s Federal Army of the Potomac crosses from Maryland to Virginia, nearly 40 days after the Battle of Antietam.

Exploring the most important 55 months in American history
George B. McClellan’s Federal Army of the Potomac crosses from Maryland to Virginia, nearly 40 days after the Battle of Antietam.
Robert E. Lee’s Confederates withdraw from Maryland as George B. McClellan proclaims a complete Federal victory in the Maryland campaign.
Robert E. Lee’s Confederates make a final stand against George B. McClellan’s Federal army before Lee decides to withdraw from Maryland and return to Virginia.
The bloodiest day in American history takes place as the armies of Robert E. Lee and George B. McClellan fight to a standoff near Sharpsburg, Maryland, along Antietam Creek.
Robert E. Lee hastily concentrates his Confederate army at Sharpsburg, Maryland, as George B. McClellan’s Federals stand ready to attack.
Robert E. Lee concentrates his Confederate Army of Northern Virginia near Sharpsburg as George B. McClellan’s Federal Army of the Potomac approaches.