The Thungyai Naresuan Wildlife Sanctuary (เขตรักษาพันธุ์สัตว์ป่าทุ่งใหญ่นเรศวร) and Huai Kha Khaeng Wildlife Sanctuary (ขตรักษาพันธุ์สัตว์ป่าห้วยขาแข้ง) are adjacent parks in the Uthai Thani, Kanchanaburi, and Tak Provinces of Western Thailand. At 622,200 hectares combined, they form the largest protected area in Southeast Asia, and were listed as a UNESCO World Heritage Site in 1991. They are best visited from Uthai Thani.
The reserves consist of almost every kind of forest found in Thailand, including mountain virgin forest, dry virgin forest, and pine forest. They have a total area of about 5,775 km². They are the watershed of rivers flowing to Srinakharin Dam.
The relatively unspoiled nature of the reserves makes them an ideal home to various rare and endangered animals such as wild buffalo, rhinoceros, wild elephants, tapirs, leopards, wild bulls, et al.
Designated points in both sanctuaries, listed below, are open to visitors. Access anywhere else in the parks or staying overnight requires permission, obtained by writing at least 15 days in advance to the Director of the Wildlife Conservation Office at the National Park, Wildlife and Plant Conservation Department, Bangkhen, Bangkok. Tel. +66 2 5614292-3 ext. 765.
- Namtok Khli Ti. "Khli Ti" in Karen language means "Suea Thon" (lone tiger). The waterfall is in Thung Yai Naresuan Wildlife Sanctuary, and its water source flows from the top of Khao Di Ka near the sanctuary. Moreover, Namtok Khli Ti Lang (น้ำตกคลีตี้ล่าง) is above Khwae Yai Lake near Khao Ngu Stream. It takes 2.5 hr to get there by boat from Kradan Pier or Mong Krathae Pier.
- Namtok Takhian Thong. The waterfall is in the area of Tanao Si Mountains, the Thai-Burmese border area in Sangkhla Buri, a part of Thung Yai Naresuan Wildlife Sanctuary. Its water source is from Myanmar, flowing along the boundary mountains leading to Thailand at Huai Song Ka Lia. Due to the forest canopy, water flows all year round. It takes 30 min to get to the first level of the waterfall on a smooth path covered with bamboo, rattan, ferns, and large trees. Sometimes, it is better to take a shortcut by passing along the stream. Tourists can experience the varying beauty of the cascades where water flows from many directions and disperses to the basin or the wider ground.
Namtok Khli Ti. "Khli Ti" in Karen language means "Suea Thon" (lone tiger). The waterfall is in Thung Yai Naresuan Wildlife Sanctuary, and its water source flows from the top of Khao Di Ka near the sanctuary. Moreover, Namtok Khli Ti Lang (น้ำตกคลีตี้ล่าง) is above Khwae Yai Lake near Khao Ngu Stream. It takes 2.5 hr to get there by boat from Kradan Pier or Mong Krathae Pier.
Namtok Takhian Thong. The waterfall is in the area of Tanao Si Mountains, the Thai-Burmese border area in Sangkhla Buri, a part of Thung Yai Naresuan Wildlife Sanctuary. Its water source is from Myanmar, flowing along the boundary mountains leading to Thailand at Huai Song Ka Lia. Due to the forest canopy, water flows all year round. It takes 30 min to get to the first level of the waterfall on a smooth path covered with bamboo, rattan, ferns, and large trees. Sometimes, it is better to take a shortcut by passing along the stream. Tourists can experience the varying beauty of the cascades where water flows from many directions and disperses to the basin or the wider ground.