The calculated distance (air line) between Castelfranco Emilia and San Martino in Rio is approximately 16 miles respectively 26 kilometers.
By car or train, the actual journey to San Martino in Rio is certainly longer, as only the direct route (as the crow flies) between Castelfranco Emilia and San Martino in Rio has been calculated here.
Air line (approximately)
26 kilometers
14 nautical miles