Route 1 (Chinese: 一號幹線) is a major artery in Hong Kong that runs in a generally north-south direction, connecting Aberdeen with Sha Tin.

Immediately after the starting point, the route intersects with Ap Lei Chau Bridge at a trumpet interchange, providing the sole road connection to the eponymous island.

Upon reaching Kowloon, Route 1 passes through the toll plaza and bus interchange of the Cross-Harbour Tunnel, situated between Hung Hom station and the Polytechnic University.

Immediately after this junction, Route 1 is joined by traffic from Chatham Road South and Hung Hom Bypass [zh].

At this point, route 1 continues to head north on Princess Margaret Road, between the neighborhoods of King's Park and Ho Man Tin.

Continuing northwards, it travels over Argyle Street via an overpass, before merging into Waterloo Road which originates from Yau Ma Tei.

The route then turns northwards, passing by City One with a partial diamond interchange leading onto Tai Chung Kiu Road.

Across the river, Route 1 reaches another partial diamond interchange with Yuen Wo Road [zh], accessible from the northern side.

The existing northbound tube (Second Lion Rock Tunnel) will be taken out of regular use, and serves as a backup carriageway during emergencies.

[4] In addition, the section of the Lion Rock Tunnel Road from the Sha Tin portals to Fung Shing Court will be widened from two to three lanes in both directions.