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