It covers an area of 122,500 rai ~ 196 square kilometres (76 sq mi) [1] of Khuan Don and Mueang Satun districts.

According to local lore, 300 years ago an earthquake formed the lake in the valley, probably due to a landslide which created a natural dam.

The rain forest is home to species of Dipterocarpus, Hopea, Shorea, Parashorea, Alstonia, Caryota and Calamus.

The deciduous forest, unusual in southern Thailand, has species of Caryota, Lagerstroemia, Pterocymbium, Vitex, Schima and Dillenia.

[2] Mammals include the endangered Malayan tapir, threatened Sumatran serow and protected marbled cat.