Phu Chong–Na Yoi National Park is a protected area at the eastern end of the Dângrêk Mountains, northeastern Thailand.[1] It is in Buntharik, Na Chaluai, and Nam Yuen districts of Ubon Ratchathani Province.[2] Established in 1987, it is an IUCN Category II protected area, measuring 686 square kilometres (265 sq mi).[3] In a mountainous area, the park borders Laos and Cambodia. Natural features include the cliffs at Pha Phueng, and the 40 metres (130 ft) Bak Teo Yai Waterfall.