The Battle of Antietam, also known as the Battle of Sharpsburg, was one of the bloodiest battles in American history. It took place on September 17, 1862, near Sharpsburg, Maryland, and was fought between the Union Army of the Potomac, commanded by Major General George B. McClellan, and the Confederate Army of Northern Virginia, commanded by General Robert E. Lee. The battle was a tactical draw, but it is generally considered to be a Union victory because it stopped Lee's invasion of the North and boosted Union morale.