The calculated distance (air line) between Lyss and La Chaux-de-Fonds is approximately 23 miles respectively 37 kilometers.
By car or train, the actual journey to La Chaux-de-Fonds is certainly longer, as only the direct route (as the crow flies) between Lyss and La Chaux-de-Fonds has been calculated here.
Air line (approximately)
37 kilometers
20 nautical miles