Phu Phaon National Park, formerly known as Huai Huat National Park with an area of approximately 517,850 rai or 828.56 square kilometers covers the area of the Muang District Khok Si Suphan District, Tao Ngoi District, Sakon Nakhon Province, Na Kae District, Nakhon Phanom Province and Dong Luang District, Kham Cha-i District, Mukdahan Province, is one of the five projects to establish a national park in honor of His Majesty the King. On the auspicious occasion of His Majesty the King's 5th Birthday Anniversary on December 5, 1987, it is the 57th national park in the country. The general topography is plateaus interspersed with sandstone mountains. Its height is about 300-600 meters above sea level. The mountain range has a turtle-backed plain about 10 kilometers long, surrounded by steep mountains. and is an important watershed of many rivers that flow into the Phung River, Huai Bang Sai, Huai Huat, Huai Lao, and 19 reservoirs, including Huai Huat Reservoir. Ta Noi Reservoir, etc.