ITRI, a town of Campania, Italy, province of Rome, 4 m. by rail from Formia. Pop. (1931) 6,081. The town is 690 ft. above sea-level, in the mountains which the Via Appia traverses between Fondi and Formia. Interesting remains of the ancient road are preserved in Itri itself ; and there are many remains of ancient buildings near it. The place was once noted for brigandage.