Fort McHenry National Monument and Historic Shrine
During the American Civil War union troops were stationed at Fort McHenry to help keep Baltimore out of the hands of those who would have Maryland join the southern rebellion. The fort's guns were turned toward the city. The fort was used as a temporary prison where political prisoners suspected of being confederate sympathizers were held, often without trial. Following the Battle of Gettysburg in early July, 1863 nearly 7,000 confederate soldiers were detained in the fort.