The calculated distance (air line) between San Donato Milanese and Reggio nell'Emilia is approximately 83 miles respectively 133 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 San Donato Milanese and Reggio nell'Emilia has been calculated here.
Air line (approximately)
133 kilometers
72 nautical miles