The calculated distance (air line) between La Spezia and Castelnovo ne'Monti is approximately 37 miles respectively 59 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 La Spezia and Castelnovo ne'Monti has been calculated here.
Air line (approximately)
59 kilometers
32 nautical miles