The calculated distance (air line) between Nahāvand and Darreh Shahr is approximately 92 miles respectively 148 kilometers.
By car or train, the actual journey to Darreh Shahr is certainly longer, as only the direct route (as the crow flies) between Nahāvand and Darreh Shahr has been calculated here.
Air line (approximately)
148 kilometers
80 nautical miles