Megara, a city of ancient Greece, capital of Megaris, about 1 m. from the Saronic gulf, opposite the island of Salamis, 20 m. AV. by N. of Athens. It consisted of a double acropolis and the city proper. The more ancient acropolis is said to have been built by Car, son of Pho-roneus; the other, together with the city, by Alcathous, son of Pelops. Subsequently a Dorian colony, under Alethes and Athemenes, took possession of the city, and enlarged it. Its original name appears to have been Po-lichne. In the 8th and 7th centuries B. C. Megara was opulent and powerful, and founded the colonies of Megara Ilyblasa in Sicily, Astacus in Bithynia, and Chalcedon and Byzantium on the Bosporus. In the time of Solon it entered into a contest with Athens for the island of Salamis, but without success. In the Persian war it contributed 3,000 heavy-armed troops and 20 ships to the confederate forces. After that struggle Megara left the Peloponnesian confederacy for that of Athens, to which ere long it became virtually subject; and the Athenians, to secure their supremacy over it, built the long walls which connected Megara with its port Nisasa. The Athenian garrison, however, was expelled by the aid of Peloponnesian troops in 445. The Athenians retaliated by excluding the Megarians from their markets and harbors, which decree operated so injuriously to the interests of the latter that its enforcement was one of the pretexts of the Spartans and their allies for the Peloponnesian war.

During that war Megara suffered severely from siege and famine, the Athenians being still in possession of Nisrea; and subsequently, though it partly recovered its prosperity, it ceased to be prominent in history. It was celebrated for its philosophical school, founded by Euclid, the disciple of Socrates. It contained noted public buildings, of which few traces remain. The present little town of Megara, which is the capital of the nomarchy of Attica and Boeotia, is dilapidated. A ferry connects it with Salamis.