The calculated distance (air line) between Zürich (Kreis 9) and La Chaux-de-Fonds is approximately 80 miles respectively 129 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 Zürich (Kreis 9) and La Chaux-de-Fonds has been calculated here.
Air line (approximately)
129 kilometers
69 nautical miles