Acheron (Acherontas) is a large river (52 kilometers long) in the Greek district of Epirus. Acheron flows through the prefectures of Ioannina, Thesprotia and Preveza. The waters of Acheron origininate from melted snow, high in the mountains of Ioannina, in addition there are several springs. The river flows in the sea at the seaside Ammoudia, on the Ionian coast.
The river is a very popular holiday destination for hikers, nature lovers, culture enthusiasts and active athletes. Canoeing, kayaking and rafting is possible here. The fauna of the river consists of an abundance of small fish, eels, crabs, frogs, butterflies and some types of harmless water snakes.
A major attraction nearby is the Necromanteion of Acheron (The Oracle of Acheron) which is located near the village Mesopotamos.