The calculated distance (air line) between Saint-Michel de l'Atalaye and Gressier is approximately 59 miles respectively 94 kilometers.
By car or train, the actual journey to Gressier is certainly longer, as only the direct route (as the crow flies) between Saint-Michel de l'Atalaye and Gressier has been calculated here.
Air line (approximately)
94 kilometers
51 nautical miles