Sawpit Bluff Plantation on Black Hammock Island was built in the 1750s by Edmund Gray and took its name from a sawpit dug for the up-and-down motion of a vertical saw blade. Its house was built of tabby, made from shells, sand, and lime. During the American Revolutionary War in the British colonial period, Continental Army soldiers and Georgia militia encamped there and fought on May 14, 1777, in the Battle of Sawpit Bluff, part of the larger Battle of Thomas Creek and one of the few Revolutionary War battles fought in Florida, before being forced to retreat by the loyalist East Florida Rangers and their Creek Indian allies. After East Florida returned to Spain in 1783, Black Hammock Island became part of a land grant to Juan Thorp, who established a large estate there called Sawpit Bluff or Barranco de Acceradero for growing Sea Island cotton and raising cattle and horses, and the plantation later passed to his daughter, Mary Thorp Smith. In 1801 and again in 1812, conflicts between American settlers moving south from Georgia and the Spanish colonial government disrupted life at Sawpit Bluff. During the War of 1812, an American force led by General George Matthews invaded the region in search of Spanish territory as part of the Patriot's War and stole a boat from the Smith family. After the war, Mary Smith's daughter Mary Martha grew up at Sawpit Bluff and married Robert Raymond Reid, Florida's fourth territorial governor. During the Civil War, Mary Martha Reid served as matron of the Florida Hospital in Richmond, Virginia, and her sister Rebecca, who also grew up there, married CSA General Joseph Finnegan, winner of the Battle of Olustee. Mary Smith eventually lost the property for unpaid taxes, the plantation fell into disuse and returned to swamp, and little remains of the old house except a few tabby remnants.