The calculated distance (air line) between Montigny-lès-Cormeilles and Sannois is approximately 2 miles respectively 4 kilometers.
By car or train, the actual journey to Sannois is certainly longer, as only the direct route (as the crow flies) between Montigny-lès-Cormeilles and Sannois has been calculated here.
Air line (approximately)
4 kilometers
2 nautical miles