ACHAIA PROPRIA, anciently a small district in the north of Peloponnesus, running westward along the bay of Corinth, and bounded on the west by the Ionian Sea, on the south by Elis and Arcadia, and on the east by Sicily; inhabitants, the Achæans, properly so called; its metropolis Patra. It is now called Romania Alta, in the Moren.
ACHAIA also denoted all those countries that joined in the Achæan league, reduced by the Romans to a province. Likewise for Peloponnesus.