Caudium (modern Montesarchio) was the main city of the ancient Caudini tribe in Samnium situated on the Appian Way between Beneventum (modern Benevento) and Capua, in what is now southern Italy. It was 21 Roman miles from Capua, and 11 from Beneventum. It, or nearby Arpaia, became the seat of an early bishopric, which is now a Latin Catholic titular see.