The calculated distance (air line) between Montigny-le-Bretonneux and Le Havre is approximately 101 miles respectively 162 kilometers.
By car or train, the actual journey to Le Havre is certainly longer, as only the direct route (as the crow flies) between Montigny-le-Bretonneux and Le Havre has been calculated here.
Air line (approximately)
162 kilometers
87 nautical miles