Doi Phu Nang National Park is situated in an approximate area of 512 square kilometers or 320,000 rai, covering the areas of Dok Kamtai District, Pong District, and Chiang-muan District of Phayao Province. There are different kinds of forests within the area of the National Park, including dense forests, mixed forests, and timber forests. The National Park also has beautiful natural sightseeing spots including Hoitonpung Waterfall, Thansawan Waterfall, which are abundant sources of rivers and gullies.
The geographical features of the National Park consist of high mountains, extending northwards. Meanwhile, Mae-yom Forest and Nampi Forest consist of high mountains extending like a horseshoe, as well as a low-lying land of Chiang-muan District situated in the middle of the two forests. Doi Phu Nang is the highest mountaintop of the two forests at the altitude of 1,202 meters (or 300 meters above the sea level) and being the source of major gullies flowing into Mae-yom River.
The average highest temperature at the National Park is 31.3°C; meanwhile, the lowest temperature is 20.2°C; and the average year-round temperature is 22.5°C. The average rainfalls within 10 years of Dok Kamtai District, Pong District, and Chiang-muan District, are 1,095 mm, 1,777.5 mm, and 1,093.2 mm respectively.
There are various kinds of forests within the areas of the National Park, including tropical evergreen forests, mixed deciduous forests, and timber forests. Major plants, which are of great economic value, include rubber trees, Malabar ironwood, Leguminosae (Pradoo), Afzelia xylocarpa Roxb., Lagerstroemia (Tabaek), Mangifera caloneura Kurz (wild mango), Ailanthus triphysa (Dennst.) Alston (Mayompa) Michelia alba, Berrya ammonilla Roxb. (Liang Mun), Schleichera oleosa (Takraw), Vitex pinnata Linn. (Teen Nok), Lithocarpus Cantleyanus (Kor), and pine wood.