The calculated distance (air line) between Lai Châu and Thái Nguyên is approximately 163 miles respectively 262 kilometers.
By car or train, the actual journey to Thái Nguyên is certainly longer, as only the direct route (as the crow flies) between Lai Châu and Thái Nguyên has been calculated here.
Air line (approximately)
262 kilometers
141 nautical miles