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. Antietam National Battlefield is located in western Maryland, 10 miles south of Hagerstown in Washington County. The best place to start your visit is at the park visitor center. The GPS address for the visitor center is 5831 Dunker Church Road, Sharpsburg, Maryland, 21782. We have brochures, museum exhibits, a film, a museum store, and park rangers and volunteers on duty to help you get oriented. The battlefield is approximately 3,000 acres that you can explore in your car or by walking. Operating Hours & Seasons: Open All Year, The Visitor Center is open daily from 9:00 a.m. to 5:00 p.m. Park Grounds are open daylight hours. Closed Thanksgiving, Christmas, and New Years Day The park has an entrance fee of $5.00 Per Person (age 16 or older; 15 and under FREE) or $10.00 Per Vehicle.