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.

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.

For the ancient Italic peoples it was a sacred river. On the shores, they erected sanctuaries such as the Demetra and Teano one.