The calculated distance (air line) between Méry-sur-Oise and Le Havre is approximately 99 miles respectively 159 kilometers.
By car or train, the actual journey to Le Havre is certainly longer, as only the direct route (as the crow flies) between Méry-sur-Oise and Le Havre has been calculated here.
Air line (approximately)
159 kilometers
86 nautical miles