Key Biscayne

Key Biscayne

Key Biscayne, although named a “key”, is not geologically part of the Florida Keys, but is a barrier island composed of sand eroded from the Appalachian Mountains, carried to the coast by rivers, and then moved along the coast from the north by coastal currents. Key Biscayne is elongated in the north-south direction, tapering to a point at each end. It is approximately 5 miles long and 1 to 2 miles wide. The northern end of the island is separated from another barrier island, Virginia Key, by Bear Cut. The southern end of the island is Cape Florida. The Cape Florida Channel separates the island from the Safety Valve, an expanse of shallow flats cut by tidal channels that extends southward about 9 miles to the Ragged Keys, at the northern end of the Florida Keys. Only Soldier Key, approximately 200 by 100 yards (183 by 91 m) wide, lies between Key Biscayne and the Ragged Keys. In 1849 the island had a fine sandy beach on the east side and mangroves and lagoons on the west side. The average elevation of the island is less than five feet above sea level.