The name of the Protected Area is Rajiv Gandhi Orang National Park. The Park is located in the districts of Darrang and Sonitpur and lies between the geographical limits of 92º15' E and 92º27' E longitudes and 26 º29' N and 26 º40' N latitudes. The total area of the Park is 79.28 km2 including the proposed first addition measuring 0.47 km2. Around 70% of the area is located in Darrang district while the remaining 30% of it lies in Sonitpur district.
The present Park area was inhabited by people till the year 1900 after which a water-borne epidemic forced the people to abandon the area. In 1915, an area comprised of 80.54 km2 was declared as a Game Reserve and formed part of Mazbat Range under Darrang Forest Division, Tezpur. Subsequently, softwood plantations were raised in the area under various Plans.
After enactment of the Wildlife (Protection) Act by the Government of India in 1972; the area was handed over to the Wildlife Wing and it was managed as an Auxiliary Area for Project Tiger. The State Government declared its intention to constitute the area as a Wildlife Sanctuary vide notification No. FRS.133/85/5 dated 20.9.1985 published in the official gazette. Upon settlements of rights, privileges and concessions, the area was finally declared as a Wildlife Sanctuary with an area of 78.81 km2 vide notification No. FRW. 28-98-116 dated 17.3.1998 published in the official gazette.
The Sanctuary was further upgraded and declared as a National Park with the same area vide notification No. FRW. 28/90/154 dated 8.4.1999. An area of 0.47 km2 was added as first addition to the Park vide preliminary notification No. FRW.06/2010/12 dated 28.10.2010 published in the official gazette.
The Park area is a shallow depression located on the northern bank of Brahmaputra River in the plains. The area is comprised of grasslands dotted with woodlands and water bodies. The vegetational succession is arrested at the grassland seral stage by annual controlled burning and uprooting of trees which colonize the grasslands. The fertile soil deposited by floods every year also promotes the growth of grasses.
Some endangered species like Bengal Florican Houbaropsis bengalensis, Greater Adjutant Stork Leptoptilos dubius, Lesser Adjutant Stork Leptoptilos javanicus , Spot-billed Pelican Pelecanus philippensis, Baer’s Pochard Aythya baeri, Blyth’s Kingfisher Alcedo hercules, Swamp Francolin Francolinus gularis etc. find a home here. The Gangetic Dolphin Platanista gangetica and seven species of turtles are found here. Further at least 20 species of anuran are found in the Park.
The simultaneous juxtaposition of three biomes- woodland, grassland and water bodies is responsible for the rich and diverse floral and faunal species.
The northern, western and north-western boundaries of the Park are well defined and demarcated on the ground by fixing pillars and digging trenches. The southern boundary is formed by Brahmaputra River which, due to its meandering course, creates small islands (chapories) almost every year. As a result, the southern boundary is not well defined. This occasionally leads to dispute with civil areas located on the left side of the river and the char areas located inside it.
Certain reference pillars may be fixed along the southern boundary, wherever possible. RCC pillars have been fixed along the northern and western boundaries. Trenches have also been dug up. But some additional pillars are required in the said areas to avoid confusion and dispute. The Park has encroachment in the eastern most part covering a compact area of 2.35 km2. As a result, the eastern boundary is not demarcated properly on the ground. The boundaries and the trench require regular maintenance as siltation rate is high due to sandy soil, heavy rainfall and floods.
The Park is connected to ecologically similar habitats, Pobitora Wildlife Sanctuary located downstream on the southern bank of Brahmaputra River, Laokhowa-Burhachapori Wildlife Sanctuary and Kaziranga National Park located upstream on the southern bank of the River. The river connection is virtually a theoretical one-way connection. The rhinos find it difficult to go upstream in the mighty Brahmaputra River. The Park is totally fragmented terrestrially i.e. it does not have any contiguous forest. The erstwhile Un-classed State Forests on the northern side have been totally degraded over a period of time. As a result, there is hardly any scope of addition to the Park except the Brahmaputra River.