BUILT: Between 1846 to 1868
OPERATION TIME: Unknown to Present
STATUS: Open as historical museum
Now a state park, Fort Delaware served as a prison for Confederate soldiers during the Civil War. Workers and tourists alike have seen ghosts, felt cold spots, and heard disembodied voices. The ghost of a Civil War soldier has been reported watching groups of tourists from the upper ramparts. The fort, which is located on an island, also has a cemetery for soldiers who died of typhus and malaria, which is supposedly haunted as well.