The calculated distance (air line) between Rosignano Solvay-Castiglioncello and Milan is approximately 156 miles respectively 251 kilometers.
By car or train, the actual journey to Milan is certainly longer, as only the direct route (as the crow flies) between Rosignano Solvay-Castiglioncello and Milan has been calculated here.
Air line (approximately)
251 kilometers
135 nautical miles