The calculated distance (air line) between Castelnuovo Rangone and San Martino in Rio is approximately 15 miles respectively 24 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 Castelnuovo Rangone and San Martino in Rio has been calculated here.
Air line (approximately)
24 kilometers
13 nautical miles