The calculated distance (air line) between Montigny-lès-Metz and Thionville is approximately 18 miles respectively 29 kilometers.
By car or train, the actual journey to Thionville is certainly longer, as only the direct route (as the crow flies) between Montigny-lès-Metz and Thionville has been calculated here.
Air line (approximately)
29 kilometers
16 nautical miles