It has about 167,013 inhabitants and is the main comune (municipality) of the Province of Reggio Emilia. The town is also named, more officially, Reggio nell'Emilia. The inhabitants of Reggio nell'Emilia (called Reggiani) usually call their town by the simple name of Reggio. In some ancient maps the town is also named Reggio di Lombardia. The old town has an hexagonal form, which derives from the ancient walls, and the main buildings are from XVI - XVIII centuries. The commune's territory is totally on a plain, crossed by the Crostolo stream.