The calculated distance (air line) between Dien Bien Phu and Xam Nua is approximately 94 miles respectively 151 kilometers.
By car or train, the actual journey to Xam Nua is certainly longer, as only the direct route (as the crow flies) between Dien Bien Phu and Xam Nua has been calculated here.
Air line (approximately)
151 kilometers
82 nautical miles