The calculated distance (air line) between Thanh Hóa and Nakhon Phanom is approximately 177 miles respectively 285 kilometers.
By car or train, the actual journey to Nakhon Phanom is certainly longer, as only the direct route (as the crow flies) between Thanh Hóa and Nakhon Phanom has been calculated here.
Air line (approximately)
285 kilometers
154 nautical miles