The calculated distance (air line) between Beaumont-sur-Oise and Cergy-Pontoise is approximately 12 miles respectively 19 kilometers.
By car or train, the actual journey to Cergy-Pontoise is certainly longer, as only the direct route (as the crow flies) between Beaumont-sur-Oise and Cergy-Pontoise has been calculated here.
Air line (approximately)
19 kilometers
10 nautical miles