The territory of Stymphalus is a plain, about six miles (10 km) in length, bounded by Achaea on the north, Sicyonia and Phliasia on the east, the territory of Mantineia on the south, and that of Orchomenus and Pheneus on the west This plain is shut in on all sides by mountains. On the north rises the gigantic mass of Cyllene, from which a projecting spur, called Mount Stymphalus (Στυμφαλος ὄρος), descends into the plain.