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.

In this last region, it gathers the waters of the River Lete and Calore, its left tributaries, and then the Torano River, the Titerno and the Isclero. The river flows meandering in the great plain, up to Capua and then continues to Castelvolturno, where it flows into the Tyrrhenian Sea close to the Oasis of Variconi.