The calculated distance (air line) between L'Isle-Adam and Marne La Vallée is approximately 27 miles respectively 43 kilometers.
By car or train, the actual journey to Marne La Vallée is certainly longer, as only the direct route (as the crow flies) between L'Isle-Adam and Marne La Vallée has been calculated here.
Air line (approximately)
43 kilometers
23 nautical miles