The calculated distance (air line) between Kazan and Mariinskiy Posad is approximately 59 miles respectively 95 kilometers.
By car or train, the actual journey to Mariinskiy Posad is certainly longer, as only the direct route (as the crow flies) between Kazan and Mariinskiy Posad has been calculated here.
Air line (approximately)
95 kilometers
51 nautical miles