The Tai Lam Chung Reservoir is also locally known as the 1000 Islands Reservoir and is the feature geographical highlight of the Tai Lam Chung Country Park in the Tuen Mun District of the New Territories. The lake was created between 1952-57 by damming the Lam Chung Valley. Because of the hilly landscape and twisting valley grounds, the flooding created a reservoir with what appears to have numerous islands, hence the nickname.
You can hike to the reservoir from several locations. The most convenient being the MacLehose Trail Section 10 which passes through the country park on the northern side of the reservoir. Around the midpoint, there is a short splinter trail that is very well marked. It is just 200 metres and leads to the Reservoir Islands Viewpoint, a fairly large area that is elevated and providing a handful of spots where you will find rewarding panoramic views of the reservoir.
Note: This is one of the most photographed locations in Hong Kong by Hongkongers so do be ready for crowds if visiting on weekends or public holidays, especially after 10am. If you want to visit on these days, best to go early or just wait and visit on normal weekdays when you won't have to deal with the crowds at the viewpoint.
Note: To access the reservoir and viewpoint from Tuen Mun, take light green minibus 43 (circular route) from just outside and across the street from V City Mall (3-4 minute walk from the Tuen Mun MTR Exit C or D). Take the mini bus to the end of the So Kwun Wat village. Get out at the last stop next to a small Tin Hau temple. Many others will be exiting here to begin the hike so don't worry about missing your stop. Further, just return to this location on the way back if you are planning to return to Tuen Mun after seeing the reservoir.