island, most northerly and second largest of the Cyclades group of Greek Aegean Islands. Andros has an area of 145 square miles (380 square km). Wooded, well-watered, and mountainous, it is an eparkhía (“eparchy”), with its capital at the town of Ándros, on the east coast. South of the capital is the port of Kórthion, which lies at the foot of the Palaiókastron (2,050 feet 【625 m】), with ruins of a Venetian castle and medieval town. The ruins of Palaeopolis, the island's ancient capital, support a hamlet, Palaiópolis, on the western coast. Figs, citrus fruits, wine grapes, and olives are grown on the island.

The ancient population was mainly Ionian. Originally dependent upon Eretria, Andros sent colonies to Chalcidice, the great peninsula of northeastern Greece, in the 7th century BC. It submitted to Persia in 490 BC and was harried by the Athenian fleet for supplying ships to the Persian king Xerxes in 480. The Athenian leader Pericles forced Ándros to admit Athenian settlers, but it revolted in 411 or 410. During the 4th century BC it was again a member of the revived anti-Spartan Delian League. In 200 it was captured by a combined Roman, Pergamese, and Rhodian fleet. It remained with Pergamum until 133 BC, when it became part of the Roman province of Asia. From AD 1207 to 1566 it was under the protection of Venice, falling to Turkey in the latter year. It became part of Greece in 1829. Pop. (1981) island, 9,020; (1991) 8,731.