The calculated distance (air line) between Bắc Kạn and Thái Nguyên is approximately 38 miles respectively 61 kilometers.
By car or train, the actual journey to Thái Nguyên is certainly longer, as only the direct route (as the crow flies) between Bắc Kạn and Thái Nguyên has been calculated here.
Air line (approximately)
61 kilometers
33 nautical miles