The starting point of Hong Kong Trail (Section 4) is located on Aberdeen Reservoir Road near Wan Chai Gap. Follow the "Hong Kong Trail" waymark into a shaded path, walk for about 300 m to the junction of trails toward Wan Chai Gap and Black's Link. Follow the directional sign for “To Black's Link via Middle Gap Road”, and soon you will arrive at a stone bridge. From there, walk for about 1 km to Locality Pillbox 13. In the late 1930s, the British garrison set up defence positions in the valleys and built over a hundred "Type A" shelters and locality pillboxes on Hong Kong Island. The Aberdeen Reservoirs Defence Position had a few locality pillboxes and "Type A" shelters. Locality Pillboxes 13 has four embrasures. Each is two-feet wide, with a 100° firing arc and was protected by iron gates. The embrasure was operated with Vickers machine gun to resist attacks from the west and south. When visiting, please respect the historic relics and refrain from entering or damaging them. After the visit, continue to the junction of trails toward Black's Link and Aberdeen Upper Reservoir. Follow the directional sign for “To Black's Link via Middle Gap Road” for about 1 km, and then walk approximately 700 m uphill. This section requires some physical effort, so please be mindful of sun protection and hydration. After completing the uphill section, continue to the Middle Gap Viewing Point, where the view is expansive, offering a distant view of Ocean Park and Brick Hill. After that, walk along a shaded path for about 900 m to the junction of trails toward Wan Chai Gap and Wong Nai Chung Gap Road. Follow the directional sign for “Wong Nai Chung Gap Road” for about 950 m, from where you can see the “Face Mask Rock” on Mount Nicholson, which from the side resembles a giant wearing a mask. Then, continue for about 1 km to Tai Tam Reservoir Road Sitting-out Area, which marks the end of Hong Kong Trail (Section 4).

_{To facilitate the public in planning their hikes, the geographical information of the route, including the route map, starting point, endpoint, and elevation chart, has been saved in a "GPX" file. The public can download hiking-related applications on their smartphones or smart watches, then click on the following "GPX" file to import the relevant information, which serves as an aid for hiking. Please note that downloading "GPX" files may increase data usage, and the functions and content display may vary depending on the device and application used.}