The calculated distance (air line) between Au and La Chaux-de-Fonds is approximately 134 miles respectively 215 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 Au and La Chaux-de-Fonds has been calculated here.
Air line (approximately)
215 kilometers
116 nautical miles