The national park, with an area of 537,424 rai ~ 860 square kilometres (330 sq mi)[2] is located in two mountain chains of the Phi Pan Nam Range, Mae Yom and Nampi, with a not-protected area in between.

Doi Phu Nang, the mountain that gives its name to the park, with an altitude of 1,202 m, is the highest peak in the area.

[4] Trees in the protected area include Malabar ironwood, Afzelia xylocarpa, Lagerstroemia calyculata, Mangifera caloneura, Ailanthus triphysa, Michelia alba, Berrya ammonilla, Schleichera oleosa, Vitex pinnata and Pterocarpus macrocarpus.

A variety of birds are found, especially the rare green peafowls, threatened by habitat destruction, which come to the park area for breeding from January to March.

Among the other animals, the fishing cat, Asiatic black bear, muntjac, masked palm civet, bamboo rat, tree shrews, the Asiatic softshell turtle and the Bengal monitor deserve mention.