Prospect Bluff Historic Sites is located in Franklin County, Florida, on the Apalachicola River, 6 miles SW of Sumatra, Florida. The site contains the ruins of two forts.
The earlier and larger one was built by the British in 1814, during the War of 1812. They allowed the members of the disbanded Corps of Colonial Marines, made up largely of fugitive slaves, and Creek tribesmen to occupy it after the British evacuated Florida in 1815, deliberately leaving their munitions behind. At that point, since the British had not named it, Americans started referring to it as Negro Fort. It was destroyed in a river attack from U.S. forces in 1816.
Fort Gadsden was built in 1818 within the former walls of the former Negro Fort.
Wikipedia https://en.wikipedia.org/wiki/Prospect_Bluff_Historic_Sites
Address 32465, United States
Coordinates 29°55'59.999" N -85°1'0.001" E