Ob Khan National Park covers the areas of Pha Samoeng National Conserved Forest including areas of Tambol Samoeng Tai, Tambol Mae Sarb, Tambol Borkaew of Samoeng District; Pa Mae Khan-Mae Wang National Conserved Forest including Tambol Mae Win, Tambol Ban Kard, Mae Wang Sub-district, Sanpatong District, Tambol San Klang of Sanpatong District; and Pha Chang-Mae Khanin National Conserved Forest including Tambol Namprae, Tambol Banpong of Hang Dong District, Chiang Mai Province, within an approximate area of 574 square kilometers or 341,875 rai. The geographical features of the National Park mostly consist of high mountains. And “Yod Khun Tien” is the highest mountaintop of the National Park, at the altitude of 1,550 meters. The National Park has beautiful natural tourist attractions and varieties of major plants and wild animals.

Topography
The geographical features of the National Park consist of high and low mountains, extending from mountains in the area of Mae Chaem District, Chaing Mai Province. The majority of mountains in the National Park are not much high. And “Yod Khun Tien” is the highest mountaintop of the National Park, at the altitude of 1,550 meters, followed by “Doi Khun Huay Prachao” at the altitude of 1,443 meters, and “Doi Khun Win” at the altitude of 1,424 meters above the medium sea level, etc. The National Park is the source of major rivers and gullies flowing into Ping River including Nan River, Lan River, Tien River, Win Gully, Mae Toa Gully, Mae Kamin Gully, Lah Luang Gully, etc. Most areas of the National Park are mountains at the average altitude of 800 meters above the medium sea level. There are small plains along rivers and gullies, including hillside plains where villages are situated.

Climate
The National Park has the tropical weather condition, i.e., summer is the longest period of the year. The weather is rather hot in summer and cold in winter. And there are frequent, short rains in the rainy season.

Flora and Fauna
Since the geographical features of the National Park consist of high and low mountains, there are various kinds of forests within the area of the National Park, including arid, evergreen forests, virgin forests, pinery, and mixed forests. Major plants include Irvingia Malayana Oliv. (Krabok), Anisoptera Costata (Krabak), Indian Mahogany, Pometia Pinnata, Sompong, rubber trees, clustered plants, Michela Alba, Talo, Cinnamon, Benzoin, Pinus Merkusii Jungh (two-leaf pines), Pinus Kesiya Royle Ex Gordon (three-leaf pines), teak, Leguminosae (Pradoo), Lagerstroemia (Tabaek), Schleichera Oleosa, Vitex Pinnata Linn. (Teen Nok), Terminalia Chebula, and different kinds of bamboo. Wild animals found in the National Park include gorals, Muliacus Muntjak, bears, fishing cats, mouse deer, masked palm civets, wild rabbits, wild boars, monkeys, slow loris, mongooses, porcupines, squirrels, tree shrews, rats, etc.