Tronzano Vercellese (Tronsan in Piedmontese) is a comune (municipality) in the Province of Vercelli in the Italian region Piedmont, located about 50 kilometres (31 mi) northeast of Turin and about 20 kilometres (12 mi) west of Vercelli. As of 31 December 2004, it had a population of 3,519 and an area of 44.9 square kilometres (17.3 sq mi).