The calculated distance (air line) between Castelnau-le-Lez and Grenoble is approximately 139 miles respectively 224 kilometers.
By car or train, the actual journey to Grenoble is certainly longer, as only the direct route (as the crow flies) between Castelnau-le-Lez and Grenoble has been calculated here.
Air line (approximately)
224 kilometers
121 nautical miles