(Greek: Ύδρα, pronounced [ˈiðra] in modern Greek) is one of the Saronic Islands of Greece, located in the Aegean Sea between the Saronic Gulf and the Argolic Gulf.
It is separated from the Peloponnese by a narrow strip of water. In ancient times, the island was known as Hydrea (Υδρέα, derived from the Greek word for “water”), a reference to the springs on the island. The municipality of Hydra consists of the islands Hydra (area 49.6 km2 (19.2 sq mi)), Dokos (pop. 18, area 13.5 km2 (5.2 sq mi)), and a few uninhabited islets, total area 64.443 km2 (24.9 sq mi). The province of Hydra (Greek: Επαρχία Ύδρας) was one of the provinces of the Piraeus Prefecture. Its territory corresponded with that of the current municipality. There is one main town, known simply as “Hydra port” (pop. 1,900 in 2011). It consists of a crescent-shaped harbor, around which is centered a strand of restaurants, shops, markets, and galleries that cater to tourists and locals (Hydriots).