Reggio nell'Emilia, usually referred to as Reggio Emilia, or simply Reggio by its inhabitants, and known until 1861 as Reggio di Lombardia, is a city in northern Italy, in the Emilia-Romagna region. It has about 171,944 inhabitants and is the main comune of the Province of Reggio Emilia.
The inhabitants of Reggio nell'Emilia are called Reggiani, while the inhabitants of Reggio di Calabria, in the southwest of the country, are called Reggini.
The old town has a hexagonal form, which derives from the ancient walls, and the main buildings are from the 16th–17th centuries. The commune's territory lies entirely on a plain, crossed by the Crostolo stream.