The calculated distance (air line) between Thổ Tăng and Thái Nguyên is approximately 33 miles respectively 53 kilometers.
By car or train, the actual journey to Thái Nguyên is certainly longer, as only the direct route (as the crow flies) between Thổ Tăng and Thái Nguyên has been calculated here.
Air line (approximately)
53 kilometers
29 nautical miles