Antietam National Battlefield is a National Park Service-protected area along Antietam Creek in Sharpsburg, Washington County, northwestern Maryland. It commemorates the American Civil War Battle of Antietam that occurred on September 17, 1862. The area, situated on fields among the Appalachian foothills near the Potomac River, features the battlefield site and visitor center, a national military cemetery, stone arch Burnside's Bridge, and a field hospital museum.