The calculated distance (air line) between Bessancourt and Le Mesnil-le-Roi is approximately 8 miles respectively 13 kilometers.
By car or train, the actual journey to Le Mesnil-le-Roi is certainly longer, as only the direct route (as the crow flies) between Bessancourt and Le Mesnil-le-Roi has been calculated here.
Air line (approximately)
13 kilometers
7 nautical miles