The river has its sources on Mount Olgassys, and in its northwestern course formed the boundary between Paphlagonia and Bithynia. It empties itself into the Euxine (Black Sea) about 90 stadia west of Amastris.
The river originates from Mount Olgassys, and in its western course established the border between Paphlagonia and Bithynia. It discharges itself into the Euxine (Black Sea) approximately 90 stadia west of Amastris.