Mae-ngao National Park is situated in Mae Hong Son Province, covering an approximate area of 257,650 rai. The National Park is a beautiful natural sightseeing spot and being the source of many rivers flowing into Salaween River.
The topography of the National Park consist of high mountains, which are the sources of many rivers flowing westwards into Salawin River of Myanmar.The waterway system of the National Park is similar to pattern of the tree diagram, consisting of a large river and its branches. Major rivers and gullies, include:
Mae-ngao River Mae-ngao River is the longest and most important river, passing the areas of the National Park for approximately 42 kilometers long, starting from Ban Sob-khong, flowing northwards to Sob-ngao and meeting Mae-yuam River. Mae-ngao River is the provincial boundary, whereas, the western part of the River is Tha Song-yang District of Tak Province, and the eastern part thereof is Sob-mei District of Mae Hong Son Province. The River is approximately 10-12 meters wide and the water is so clear that it is called Mae-ngao River. In the rainy season, the River, which is used as a water transport route to Sob-mei District by tribesmen, has the very rapid water. Many gullies within the National Park, which flow into Mae-ngao River, include Huai Mae Loh-noi, Huai Mae-bang, Huai Mae Lela-kro, Huai Oloh-gro, Huai Kong-oum, etc.
Mae-yuam River Mae-yuam River flows from Khun-yuam District, passing Mae La-noi District and meeting Mae-ngao River at Ban Sob-ngao, Sub-District Mae-sod of Sob-mei District and meeting Mei District at Ban Sob-yuam, Sub-District Mae Sam-laeb and flowing into Salaween River. The River is approximately 215 kilometers long, and being considered as one of the major rivers of Mae Hong Son Province.The River flows southwards, passing the western area of the National Park for approximately 14 kilometers long.
Rid River The River is situated in the north of the National Park, flowing westwards to Sub-District Kong-koi, Sub-District Mae-suad, and meeting Mae-yuam River in the south of Ban Mae-suad.
Huai Mae-khong The Gully flows from Om-koi District and meets Mae-ngao River at Ban Sob-khong.
Since the topography of the National Park consist of high mountains and water sources, the weather at the National Park can be divided into 3 seasons including the rainy season (June-October) of which average rainfall is 1,120 mm/year; winter (November-February), when the weather is cold and foggy; and summer (March-May), when the average highest temperature is 35°C.
There are various kinds of forests within the areas of the National Park, including mixed deciduous forests of which major plants include teaks, Xylia xylocarpa (redwood plants), Terminalia arjuna (Rokfa), Black Wood, Dalbergia assamica (Ked-dum), Leguminosae (Pradoo), etc.; evergreen forests of which major plants include Lithocarpus cantleyanus (Kor), Aristolochia indica Linn. (Kra-chao Sida), moss, and lower plants include ferns, Bromheadia finlaysoniana Reichb.f. (ground orchids), ginger, etc.; timber forests, which can be found in the areas of hills, shoulders, foothills, and of which major plants include timbers, Shorea siamensis (Rang), Dipterocarpus tuberculatus (Pluang), Dipterocarpus intricatus (Hiang), Dillenia aurea Smith (Ma-San), Malacca tree, Morinda elliptica (Yor-Pa), and lower plants include grasses.
Since the topography of the National Park consist of high mountains and virgin forests,wild animals found in the areas of the National Park can be divided into categories, as follows
According to the exploration of the National Park, there are different kinds of mammals including wild boars, masked palm civets, Asiatic black bears, Muntiacus muntjak, monkeys, langur, gibbons, goral, flying squirrels, foxes, Asiatic wild dogs, wild rabbits, small bamboo rats, etc.
Birds found in the areas of the National Park include red jungle fowls, Malayan koel, singing myna, turtle doves, Drongo, blue magpie, coucal, stripe-breasted quail, Ga-hang, Nuthatch, Greater Green-billed Malkoha, barn owls, Kra-wan, Trogon, tailor-bird, black-billed roller, etc.
Reptiles found in the areas of the National Park include cobra, banded krait, constrictors, rat snakes, etc.
Amphibians inhabiting in the areas of the National Park include small green frogs found in Mae-ngao River.
Fish found in rivers include spiny eels, giant gourami, green fish, gobies, estuarine catfish, crocodile fish, etc.