Antietam was the Bloodiest One Day Battle in American History. 23,000 soldiers were killed, wounded or missing after twelve hours of savage combat on September 17, 1862. The Battle of Antietam ended the Confederate Army of Northern Virginia's first invasion into the North and led to Abraham Lincoln's issuance of the preliminary Emancipation Proclamation.
The Visitor Center has museum exhibits, a Museum Store, a 26-minute introductory film "Antietam Visit" shown on the hour and the half- hour (except from noon - 1:00 p.m.) and a one-hour "Antietam Documentary" shown every day in the visitor center from noon - 1:00 p.m.
Visitors can join a Park Ranger for battlefield talks and walks; take a self-guided 8 1/2 mile auto tour with 11 stops through the battlefield; take a self-guided hike on the Bloody Lane, Cornfield, Final Attack, Union Advance, Antietam Remembered, Sherrick Farm or Snavely Ford Trails; and tour the Pry House Field Hospital Museum (check at the visitor center for hours).
The website has a battlefield scavenger hunt that can be printed out before touring the battlefield.