Collagna is a comune (municipality) in the Province of Reggio Emilia in the Italian region Emilia-Romagna, located about 90 kilometres (56mi) west of Bologna and about 50 kilometres (31mi) southwest of Reggio Emilia. As of 31 December 2004, it had a population of 1,004 and an area of 67.0 square kilometres (25.9sqmi).