The calculated distance (air line) between Châteauneuf-les-Martigues and Saint-Étienne is approximately 147 miles respectively 236 kilometers.
By car or train, the actual journey to Saint-Étienne is certainly longer, as only the direct route (as the crow flies) between Châteauneuf-les-Martigues and Saint-Étienne has been calculated here.
Air line (approximately)
236 kilometers
127 nautical miles