The longest river of Southern Italy with its 175 kilometres rises in Molise, at Rocchetta a Volturno and runs for a long way in the Apennine region, of which, after the Ponte 25 archi, marks the border with Campania.
It rises at the foot of Mounts Trebulani, at 86 meters above sea level, in the territory of Calvi Risorta.
For the ancients, it was the river of the myth, which gave forgetfulness to whoever drunk its water.
It is an artificial lake, created in the 1960s to power the electricity station of Capriati al Volturno.