The calculated distance (air line) between Jämsänkoski and Nurmijärvi is approximately 101 miles respectively 163 kilometers.
By car or train, the actual journey to Nurmijärvi is certainly longer, as only the direct route (as the crow flies) between Jämsänkoski and Nurmijärvi has been calculated here.
Air line (approximately)
163 kilometers
88 nautical miles