The calculated distance (air line) between Trezzo sull'Adda and Boltiere is approximately 3 miles respectively 5 kilometers.
By car or train, the actual journey to Boltiere is certainly longer, as only the direct route (as the crow flies) between Trezzo sull'Adda and Boltiere has been calculated here.
Air line (approximately)
5 kilometers
3 nautical miles