A Confederate POW cemetery was created here in 1863. The POWs were held in Fort Delaware. Earthwork fortifications were also built here for ten (15-inch and 10-inch) Rodman guns on wooden carriages and platforms. Finns Point Battery was first located here in 1872. Only two gun emplacements and five magazines in the mortar battery were completed before construction was halted. Two 1872 magazines remain, and one was used again during the Endicott period. It has an early observation post on it. The current fort was created in 1897 beginning with a "6-gun battery" which eventually became Batteries Harker and Arnold. Along with Fort DuPont, it was built to compliment Fort Delaware.