屯門公路
At San Tin Interchange near Lok Ma Chau, Route 9 turns south towards Au Tau, near Yuen Long onto an expressway known as the San Tin Highway. After interchanging with Route 3, Route 9 runs along the Yuen Long Highway to Lam Tei Interchange, followed by Tuen Mun Road, all the way to Tsuen Wan.