The calculated distance (air line) between Lào Cai and Dien Bien Phu is approximately 97 miles respectively 157 kilometers.
By car or train, the actual journey to Dien Bien Phu is certainly longer, as only the direct route (as the crow flies) between Lào Cai and Dien Bien Phu has been calculated here.
Air line (approximately)
157 kilometers
84 nautical miles