Huay Mae Sak Waterfall Forest Park located in Nam Tok Pattana Village, Moo 7; Tung Kor King Sub-district, Viang Chiang Rung District, Chiang Rai Province, situated in Pah Huay Sak National Reserved Forest and eastern Mae Kok Forest, covered the area of approximately 2,800 rais. The Royal Forest Department declared this forest park on May 8, 2002.

Topography
The mountain laid from southwest towards northeast, approximately 460-963 metres above the average sea level and 30% average slope. Huay Mae Sak is a big stream in this area and the water flows throughout the year. It’s the watershed area of Huay Mae Sak Waterfall that is flowing through the area.

Flora and Fauna
It’s Mixed Deciduous Forest where teak is available. Forest around the Huay Sak Waterfall is still abundant. However, it’s different in other area because the encroachment in the past. Presently the forest has been recovered. Flora species found consist of Lagerstroemia balansae, teak, Mitragyna brunonis, Melia azedarach, Bischofia javanica, etc. Ground plants consist of bamboo species, wild banana, Spilanthes iabadicensis, Imperata cylindrica, Siam weed, wild jam, Cyperaceae genus, Araceae genus and fern.
Fauna found consists of wild rabbit, bay bamboo rat, Indochinese ground squirrel, mongoose, jungle fowl, coucal, thick-billed pigeon, white-rumped shama, red-whiskered bulbul, amphibian, reptile, and various fishes.