The island totals 6.4 acres (2.6 hectares) and houses a mixture of disused fortifications and military accommodation built over hundreds of years having been fortified originally as a defence against the French and Spanish. It ceased being used for military
purposes after WWII. Stairs from the jetty lead up to the raised fortified area. The jetty which provides access to the island, is on a small beach on the north of the island. A further beach lies to the northwest of the island. The island's geology is made up of volcanic tuff and lava along with marine limestone.