The calculated distance (air line) between Montigny-lès-Cormeilles and Reims is approximately 85 miles respectively 137 kilometers.
By car or train, the actual journey to Reims is certainly longer, as only the direct route (as the crow flies) between Montigny-lès-Cormeilles and Reims has been calculated here.
Air line (approximately)
137 kilometers
74 nautical miles