The calculated distance (air line) between Tuen Mun San Hui and Ma On Shan is approximately 17 miles respectively 27 kilometers.
By car or train, the actual journey to Ma On Shan is certainly longer, as only the direct route (as the crow flies) between Tuen Mun San Hui and Ma On Shan has been calculated here.
Air line (approximately)
27 kilometers
15 nautical miles