The largest wildlife preserver in the state of Assam, the Dibru-Saikhowa National Park and Biosphere Reserve is situated on the alluvial flood plains of Brahmaputra in Upper Assam. The `Land of Rising Sun`, Arunachal Pradesh is located adjacent to the national park. The park covers a vast area of 650 sq. km and situated only 13 kms away from the Tinsukia town. It is bounded by the Brahmaputra River and Arunachal Hills in the north and Dibru and Patkai hills on the south. The park was declared as a wildlife Sanctuary in 1986 by the State Government of Assam. The Government united two Reserve forest, named Dibru and Saikhowa and included some other areas and established this National Park and Biosphere Reserve. The Government of India elevated the park to National Park, in the year 1999. The core area of the park is spread over 340 sq. km. and it has a large buffer zone, as well. The Dibru-Saikhowa National Park and Biosphere Reserve provides natural habitat to a large variety of flora and fauna species.

The Dibru Saikhowa National Park and Biosphere Reserve is one of the 19 (nineteen) biodiversity hotspots in the world. The park is located at an altitude of 118 m above sea level. Biogeographically, the area exhibits the properties of both the Indian and Malayan sub regions and represents the North Eastern India-Brahmaputra valley Bio-geographical province (9A). The park has a tropical monsoon climate with a hot and wet summer and cool and usually dry winter. It receives annual rainfall in the range of 2300 mm to 3800 mm and the main rainy months are June, July, August, and September. The annual temperature of the area ranges from 7° C to 34° C. While, the months of June, July and August are the hottest, the months of December and January are the coolest months in the park.

Natural vegetation in the Dibru-Saikhowa National Park and Biosphere Reserve is principally comprised of semi-evergreen forests, deciduous forests, littoral and swamp forests and patches of wet evergreen forests, bamboo, cane brakes and grasslands. A great variety of Orchid also blossom in the park. Being an ideal habitat for many animals and birds, the park is counted amongst the most vibrant wildness on earth. It is distinct for its pristine scenic beauty. The main species of the Orchid flora found in the park include Salix tetrasperma, Bischofia javanica, Dillenia indica, Bombax ceiba, Terminalia myriocarpa, Lagerstroemia parviflora, Mesua ferrea, Dalbergia sissoo, Ficus spp. etc. The species like Arundo donax, Imperata cylindrica, Phragmaties karka, Erianthus ravanea, Saccharum spp. are some of the dominant species of grasses in the National Park.

The park was primarily established for conserving the White-Winged Wood Duck in its natural habitat. However, the park later became famous for its Bright Coloured Wild White-Winged Wood Duck Horses, also known as Feral Horses. Out of the 36 species of mammals found in the park, 12 are listed in the schedule 1 of Wild life (Protection) Act 1972. Some of the most important mammal species found in the park include the Royal Bengal Tiger, Leopard, Clouded Leopard, Jungle Cat, Sloth Bear, Dhole, Small Indian Civet, Malayan Giant Squirrel, Chinese Pangolin, Gangetic Dolphin, Slow Loris, Pig Tailed Macaque, Assamese Macaque, Rhesus Macaque, Capped Langur, Hoolock Gibbon, Asian Elephant, Wild Boar, Sambhar, Hog Deer, Barking Deer, Asiatic Water Buffalo, etc. Apart from these, the reptiles species found in the park include 2 species of Monitor Lizards, 8 species of Turtles and 8 species of Snakes. 62 different species of fishes have been recorded from the Dibru-Saikhowa National Park and Biosphere Reserve, as well.

Besides, the rich variety of natural vegetation and mammal fauna species, the Dibru-Saikhowa National Park and Biosphere Reserve is also home to more than 350 species of birds. The bird species are of both resident and migratory types. The local and migratory birds found in the numerous water bodies of the park include the White Winged Wood Duck, Bengal Florican, Great East Indian Hornbill, East Indian Pied Hornbill, Spot Billed Pelican, Greater Adjutant Stork, Lesser Adjutant Strok, Pallas`s Fishing Eagle, Greater Spotted Eagle, Swamp Fran Colin, Blyth`s Kingfisher, Great Grebe, Indian Shag, Grey Heron, Purple Heron, Night Heron, Yellow Bittern, Open-bill Stork, Black Stork, Large Whistling Teal, Griffon Vulture, Osprey, Crested Serpent Eagle, March Babbler, Jardon`s Babbler, Black Breasted Parrot-bill, etc.

Apart from being a protector and conserver of the great variety of wildlife in the region, the Dibru-Saikhowa National Park and Biosphere Reserve is also considered as a favourite tourist destination. Several tourists from throughout India and also from all over the world come and visit the park, on a regular basis. Permission is needed for entry into the park and one can enter through the Guijan Ghat (10km from Tinsukia) and the Saikhowa Ghat. The park is generally open for the tourists during the months of November to April or as notified by the National Park Authority.