Cavaglià is a comune (municipality) in the Province of Biella in the Italian region Piedmont, located about 50 km northeast of Turin and about 20 km south of Biella. As of 31 December 2004, it had a population of 3,644 and an area of 25.5 km². Cavaglià borders the following municipalities: Alice Castello, Carisio, Dorzano, Roppolo, Salussola, Santhià.