The calculated distance (air line) between Luang Namtha and Ban Houakhoua is approximately 78 miles respectively 126 kilometers.
By car or train, the actual journey to Ban Houakhoua is certainly longer, as only the direct route (as the crow flies) between Luang Namtha and Ban Houakhoua has been calculated here.
Air line (approximately)
126 kilometers
68 nautical miles