With a surface of over 1500 square kilometers, the limestone massif of Matese stretches between Molise and Campania and falls within the territory of four provinces.

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 from Lake Matese and in the first part of its way, it is characterised by cascades and differences in heights.

It rises at the foot of Mounts Trebulani, at 86 meters above sea level, in the territory of Calvi Risorta.