The calculated distance (air line) between Sassuolo and Castelnovo ne'Monti is approximately 20 miles respectively 33 kilometers.
By car or train, the actual journey to Castelnovo ne'Monti is certainly longer, as only the direct route (as the crow flies) between Sassuolo and Castelnovo ne'Monti has been calculated here.
Air line (approximately)
33 kilometers
18 nautical miles