The calculated distance (air line) between Blois and Saint-Jean-le-Blanc is approximately 34 miles respectively 55 kilometers.
By car or train, the actual journey to Saint-Jean-le-Blanc is certainly longer, as only the direct route (as the crow flies) between Blois and Saint-Jean-le-Blanc has been calculated here.
Air line (approximately)
55 kilometers
30 nautical miles