Khao Sok National Park (Thai: เขาสก) is in Surat Thani Province, Thailand. Its area is 739 km², and it includes the 165 square kilometer Cheow Lan Lake contained by the Ratchaprapha Dam. The park is the largest area of virgin forest in southern Thailand and is a remnant of rain forest which is older and more diverse than the Amazon rain forest. Being the most popular mainland national park destination in South Thailand, Khao Sok is a rainforest with great diversity of plants and wildlife. It is one of the few bigger national parks in the country relatively easily accessible by public services from nearby Phuket, Krabi, Khao Lak, Surat Thani, Ao Nang (Railey Beach). The main attractions of the park are iconic limestone hills, waterfalls accessible by hiking through the lush jungle, raft houses sperad over Khao Sok lake, caves, few waterstreams of which Sok River is the most popular one.