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.

In the north-east of Campania Felix, separated from the Campania Apennines by the valley of the Medio Volturno, the massif of the Trebulani Mountains rises, also known as the Colli Caprensi.

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 extinct volcano of Roccamonfina is the heart of the park that protects since 1993 a territory of great naturalistic value from Campania Felix up to the border with Lazio. Eleven thousand hectares of volcanic rocks and limestone, streams and lush vegetation, dotted with ancient hamlets keeping alive the imprint of their past and the heritage of their identities.

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 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.