The Monti Ernici (Italian: Mountains of the Hernici) are a mountain range in central Italy, part of the sub-Apennines of Lazio. They are bounded by the valley of the river Aniene to the north-east, that of the Liri to the east, and, from south to west, by the valleys of the Cosa and Sacco. They are the natural border between the Ciociaria and the Abruzzo.