Sai Kung East Country Park, National park on Sai Kung Peninsula, Hong Kong.

Sai Kung East Country Park covers 4,477 hectares of the Sai Kung Peninsula, from Pak Tam Road east to High Island, Long Harbour and Tai Long Wan. Its hills are built of 150–170-million-year-old volcanic rhyolite, with hexagonal rock columns up to 1.2 m across. The High Island Reservoir, completed in 1978, holds 281 million cubic metres behind two dams over 64 m above sea level.

Sai Kung East Country Park was designated in 1978, covering 4,477 hectares east of Pak Tam Road, including High Island Reservoir, Long Harbour, Tai Long Wan, Pak Tam Au, Sheung Yiu and Wong Shek Pier. The reservoir works ran from 1969 to 1978: two dams over 64 metres above sea level sealed off the Kwun Mun Channel, the first time a natural coast was enclosed by dams for a reservoir. Villages such as 19th-century Sheung Yiu, now a museum, predate the park.

Villages in the park include Sheung Yiu, a Hakka settlement built in the late 19th century by the Wong clan from Huangcaoling in Bao'an, Guangdong; its houses, watchtower, pigsties and threshing floor now form the Sheung Yiu Folk Museum. Tai Long Village is over 250 years old and Ham Tin Village over 150, both listed as Grade II historic buildings. The Tin Hau Temple at Tung A on High Island dates from 1741, and the Chapel of the Immaculate Conception at Tai Long Village from about 1867.

Entry to the park starts at Pak Tam Chung, where different trails begin at various difficulty levels. Plan to wear sturdy footwear and bring plenty of water, as the terrain can be uneven and exposed.

The High Island Reservoir was the first reservoir in the world formed by damming a natural sea channel, the Kwun Mun Channel. Its two main dams rise 64 metres above sea level, over 100 metres from their foundations, and hold 281 million cubic metres, the largest capacity in Hong Kong. Construction ran from 1969 to 1978.