The calculated distance (air line) between Buchs and La Chaux-de-Fonds is approximately 62 miles respectively 100 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 Buchs and La Chaux-de-Fonds has been calculated here.
Air line (approximately)
100 kilometers
54 nautical miles