The calculated distance (air line) between Choisy-le-Roi and Cergy-Pontoise is approximately 24 miles respectively 39 kilometers.
By car or train, the actual journey to Cergy-Pontoise is certainly longer, as only the direct route (as the crow flies) between Choisy-le-Roi and Cergy-Pontoise has been calculated here.
Air line (approximately)
39 kilometers
21 nautical miles