Geographically, Achaea was (and is) the northernmost region of the Peloponnese, occupying the coastal strip north of Arcardia. To the south, it bordered Arcadia along the ridge of high ground running from Mount Erymanthos to Mount Cyllene. To the east, it bordered Corinthia near to the city of Sicyon, and to the west the Larissos river and western ridge of Erymanthos formed the border with Elis. Apart from the plain around Dyme, to the west, Achaea was generally a mountainous region.