The calculated distance (air line) between Colorno and Reggio nell'Emilia is approximately 20 miles respectively 32 kilometers.
By car or train, the actual journey to Reggio nell'Emilia is certainly longer, as only the direct route (as the crow flies) between Colorno and Reggio nell'Emilia has been calculated here.
Air line (approximately)
32 kilometers
18 nautical miles