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