The calculated distance (air line) between La Roche-sur-Foron and Grenoble is approximately 68 miles respectively 109 kilometers.
By car or train, the actual journey to Grenoble is certainly longer, as only the direct route (as the crow flies) between La Roche-sur-Foron and Grenoble has been calculated here.
Air line (approximately)
109 kilometers
59 nautical miles