Nam Tok Huai Yang National Park covers the area of Amphur Bang Sapan and Tab Sakae of Prachuap Kiri Khan province. It is encompassed by many beautiful places. The park was designated on the 8th December 1991 as the 70th national park of Thailand, with total area of 161 sq.km.

The park is steeply mountainous on Tanao Sri mountain range at 100 - 1,200 meters above sea level. It is watershed of many rivers, which border Thai and Myanmar.

The weather in this area consists of three seasons.
The summer is from February to April.
The rainy season is from May to November.
The winter is from December to January.

The park is covered by evergreen and dry evergreen forest, important trees are Hopea odorata, Lagerstoemia tomentosa, Terminalia corticosa, Dipterocarpus species, Toena ciliata and bamboo. Wildlife are abundant, for example serow, langur, gibbon, squirrel, wild pig, leopard, barking deer and porcupine and birds.