Dokos (Greek: ?????) is a small Greek island of the Argo-Saronic Gulf, adjacent to Hydra, and separated from the Peloponnese by a narrow strait called on some maps "the Hydra Gulf." It is part of the municipality of ?dra (Hydra) in Piraeus Prefecture and reported a population of 13 persons at the 2001 census. The island is populated only by some Orthodox monks and perennial sheep herders. The island is rocky reaching a height of 308 meters. It has since the ancient years considered to be a strategic location. On the east side you can find the ruins of a great Byzantine - Venetian Castle. During the Greek War of Independence Dokos was used by the forces of Hydra as a port.