The calculated distance (air line) between Donghai and Yuen Long Kau Hui is approximately 108 miles respectively 174 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 Donghai and Yuen Long Kau Hui has been calculated here.
Air line (approximately)
174 kilometers
94 nautical miles