The barn, located near the Philip Pry House, is operated by the National Museum of Civil War Medicine in nearby Frederick. It opened to the public earlier this week.
The museum invites battlefield visitors to stand on the site where the wounded were treated and learn about medical concepts that were pioneered during the war between the states.
The Battle of Antietam was the bloodiest one-day battle of the war. Nearly 23,000 soldiers were killed, wounded, captured or declared missing there on September 17th, 1862.
For more information visit www.nps.gov/archive/anti/Pry_House.htm