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