Note:  Do not rely on this information. It is very old.

Megaris

Megaris, the name of the district surrounding the town of Megara, and comprising about 143 square miles of the broader part of the Isthmus of Corinth. It is traversed by the range of Geraneia, and the only plain it possesses is the White Plain, upon which Megara stood. This town attained great power in the 8th century B.C. Constitutional troubles ensued and weakened the state, which could not resist the growing influence of Athens. Megara allied herself with Athens in the struggle against Sparta, but changed sides, and suffered terribly. In the Roman period the place still flourished, but afterwards decayed. Theognis, Susarion, and Euclid (the philosopher, not the more famous geometrician) were amongst it greatest citizens.