The island is named for its early owner, Lewis Deméré (1813 – About 1880), who was born at St. Simons Island, Georgia. He and his wife, Virginia Clancy Barnard Deméré (1821–1900) and son, Raymond Barnard Deméré (1843–1905) lived on the island until about 1880. Credit Wikipedia

Demere Key is the home to the Sea Grape Lodge, which is now a private residence. Phil DeGraff bought the island from Harry Stringfellow May 9, 1954. Stringfellow spent thousands of dollars putting in a causeway from end of Maria Drive out to Demere Key. Construction for the Sea Grape Lodge began in 1955 and the lodge opened February 9, 1958. Sea Grape Lodge was sold to private owners in 1972 and closed to the public.

On June 13, 1972, it was added to the U.S. National Register of Historic Places.