The Huai Kha Khaeng Wildlife Sanctuary is located in Uthai Thani and Tak Provinces, Thailand. The sanctuary was established in 1974, and is one of the largest and most important protected wildlife areas in Southeast Asia. The wildlife sanctuary was declared a World Heritage Site by the United Nations in 1991. The protected area is home to a diverse range of animals including large mammals, birds, and reptiles. It is Thailand's premier Wildlife research sanctuary.