The calculated distance (air line) between La Chapelle-Saint-Mesmin and Cergy-Pontoise is approximately 80 miles respectively 129 kilometers.
By car or train, the actual journey to Cergy-Pontoise is certainly longer, as only the direct route (as the crow flies) between La Chapelle-Saint-Mesmin and Cergy-Pontoise has been calculated here.
Air line (approximately)
129 kilometers
70 nautical miles