One place we didn't want to miss, on our tour of Civil War battlefields, was Antietam, located near Sharpsburg, Maryland - just three hours south of where we are (temporarily) located in Pennsylvania. It was following this Union victory that President Lincoln issued the Emancipation Proclamation designed to further weaken the Confederacy.
Antietam is considered the bloodiest one-day battle the United States has ever experienced. There were more casualties in this one day than in the Revolutionary War, the War of 1812 and the Mexican War combined. Antietam had even more casualties than we experienced during D-Day.
We began our visit at the small museum explaining the battle that took place on September 17, 1862, a year and a half into the Civil War. Confederate forces had won more of the battles, at this point in the war, and President Lincoln sorely needed a Union victory.
Antietam was General Lee's first foray onto Union soil and General George McClellan was trusted to repel this Confederate attack.