The calculated distance (air line) between Tuen Mun and Yuen Long Kau Hui is approximately 6 miles respectively 9 kilometers.
By car or train, the actual journey to Yuen Long Kau Hui is certainly longer, as only the direct route (as the crow flies) between Tuen Mun and Yuen Long Kau Hui has been calculated here.
Air line (approximately)
9 kilometers
5 nautical miles