The calculated distance (air line) between Fortress Hill and Tuen Mun San Hui is approximately 16 miles respectively 26 kilometers.
By car or train, the actual journey to Tuen Mun San Hui is certainly longer, as only the direct route (as the crow flies) between Fortress Hill and Tuen Mun San Hui has been calculated here.
Air line (approximately)
26 kilometers
14 nautical miles