The calculated distance (air line) between Monsummano Terme and Castelfranco di Sotto is approximately 12 miles respectively 19 kilometers.
By car or train, the actual journey to Castelfranco di Sotto is certainly longer, as only the direct route (as the crow flies) between Monsummano Terme and Castelfranco di Sotto has been calculated here.
Air line (approximately)
19 kilometers
10 nautical miles