The calculated distance (air line) between Montesson and Montigny-lès-Cormeilles is approximately 6 miles respectively 9 kilometers.
By car or train, the actual journey to Montigny-lès-Cormeilles is certainly longer, as only the direct route (as the crow flies) between Montesson and Montigny-lès-Cormeilles has been calculated here.
Air line (approximately)
9 kilometers
5 nautical miles