Fort Gorges is a former United States military fort built on Hog Island Ledge in Casco Bay, Maine. Built from 1858 to 1864, no battles were fought there and no troops were stationed there. Advancing military technology, including iron clad ships and long range guns, made the fort obsolete before it could be used. The fort is now a park, accessible only by boat. It was added to the National Register of Historic Places in 1973.