It starts in the area of Frosinone from the confluence between the Liri, which first crosses Abruzzo and Lazio, and the Gari, which rises at Cassino and is often called Liri-Garigliano.

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

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

It is one of the favourite stopping points in the long spring migration from Africa to Central Eastern Europe on the Tyrrhenian route.

With a surface of just over a square kilometer, the enchanting Lake of Letino was created at the beginning of the twentieth century in order to feed the hydroelectric power station of Prata Sannita.

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.