The calculated distance (air line) between Nakhon Phanom and Kamalasai is approximately 109 miles respectively 175 kilometers.
By car or train, the actual journey to Kamalasai is certainly longer, as only the direct route (as the crow flies) between Nakhon Phanom and Kamalasai has been calculated here.
Air line (approximately)
175 kilometers
94 nautical miles