The calculated distance (air line) between Nakhon Phanom and Sakon Nakhon is approximately 45 miles respectively 73 kilometers.
By car or train, the actual journey to Sakon Nakhon is certainly longer, as only the direct route (as the crow flies) between Nakhon Phanom and Sakon Nakhon has been calculated here.
Air line (approximately)
73 kilometers
39 nautical miles