The calculated distance (air line) between Blois and Saint-Cyr-sur-Loire is approximately 34 miles respectively 54 kilometers.
By car or train, the actual journey to Saint-Cyr-sur-Loire is certainly longer, as only the direct route (as the crow flies) between Blois and Saint-Cyr-sur-Loire has been calculated here.
Air line (approximately)
54 kilometers
29 nautical miles