The calculated distance (air line) between Cầu Diễn and Thái Nguyên is approximately 39 miles respectively 62 kilometers.
By car or train, the actual journey to Thái Nguyên is certainly longer, as only the direct route (as the crow flies) between Cầu Diễn and Thái Nguyên has been calculated here.
Air line (approximately)
62 kilometers
34 nautical miles