Achaia, one of the ancient divisions of the Peloponnesus, extending along the coast of the gulf of Corinth; greatest length from E. to W. about 65 m.; breadth, 12 to 20 m.. Patras, formerly Patrae, is the only Achaean town that has preserved any importance. The country was originally called Aegialea, that is, the coastland, and inhabited by Ionians, who were dispossessed by the Achaeans on the conquest of the Peloponnesus by the Dorians. After the Roman conquest of Greece and Macedonia, the province of Achaia included all Peloponnesus, with X. Greece S. of Thessaly.- In the present kingdom of Greece it forms a nomarchy or province with Elis; area, 3,090 sq. m.; pop. in 1870, 149,561. Capital, Patras. (See Achaean League, and Achaeans.)