a rocky island in the Grecian Archipelago, 6 miles off the coast of Argolis. It is 12 miles in length, from N.E. to S.S.W., by 3 in breadth. The surface presents scarcely a speck of vegetation, and the inhabitants are entirely dependent on trade and commerce. Its insular position and facilities for trade pointed it out as a suitable place of refuge from the oppression of the Turks. At the commencement of the war of independence it had no fewer than 150 vessels, while the bravery of the people, and their efficiency as seamen, contributed in no small degree to the successful issue of that contest. The town of Hydra, which, with the exception of two adjacent villages, is the only inhabited part of the island, is situated on the N.W. side, and rises abruptly from the harbour in successive tiers in the form of an amphitheatre. The harbour is a deep bay, neither spacious nor secure. In 1825 the population of the island was estimated at 40,000; but at present it does not amount to more than half that number.