Khao Sok national park is positioned in Surat Thani province in Thailand. Its ground area is 739 km², and it includes the Chiao Lan reservoir dammed by the Ratchaprapha dam. The commons encompasses the largest area of virgin forest in Southern Thailand and is a remnant of rainforest which is older and more varied than the Amazon Rainforest. The undomesticated mammals include, Malayan Tapir, Asian Elephant, Tiger, Sambar Deer, Bear, Guar, Banteng, Serow, Wild Boar, Pig Tailed Macaque, Langur, White handed Gibbon, Squirrel, Muntjak and Mouse Deer.
It is perhaps most well-known for the Bua Phut flower which produces within the park. In addition to its foreign flora, Khao Sok is inhabited by a wide variety of animals, including gibbons and barking deer.
The Ninety four meter high Ratchaprapha dam was built in 1982 at the Khlong Saeng River, a tributary of the Phum Duang River.