Sundarbans, formerly Sunderbunds, vast tract of forest and saltwater swamp forming the lower part of the Ganges Delta, extending about 160 miles (260 km) along the Bay of Bengal from the Hooghly River Estuary (India) to the Meghna River Estuary in Bangladesh. The Sundarbans are a part of the world's largest delta formed by the rivers Ganges, Brahmaputra and Meghna. The whole tract reaches inland for 60-80 miles (100-130 km).A network of estuaries, tidal rivers, and creeks intersected by numerous channels, it encloses flat, marshy islands covered with dense forests.A network of estuaries, tidal rivers, and creeks intersected by numerous channels, it encloses flat, marshy islands covered with dense forests.
Just south of Calcutta, Sunderban is one of the most unique ecosystems in this part of the world. It is dominated by mangrove forests and gets its name from the Sundari (Heritiera foams) trees. Situated at the mouths of the Ganges, Sunderban spreads over 54 islands and two countries (India's West Bengal and Bangladesh) and is part of the world's largest delta region. Sunderban covers an area of 4262 sq. kms in India. The Sunderban Tiger Project was started in 1974 and has an area of 2585 sq. kms. The core area is 1330 sq. kms and is a national forest and UNESCO world heritage site. Sunderban is home to the largest number of wild tigers in the world.
The Sundarbans Tiger Reserve, created in 1973, was the part of the then 24-Pargans Division. 
,Subsequently the area comprising of the present tiger reserve was constituted as Reserve Forest in 1978. Sundarbans in West Bengal is the estuarine phase of the Ganges as well as Brahmaputra river systems. This littoral forest is the only ecological habitat of the tiger of its kind not only in India but also in the world except in Bangladesh. The typical littoral forests of Sundarbans comprises of a host of trees species adopted to the peculiar estuarine condition of high salinity, lack of soil erosion and daily inundation by high tides. The tidal forms and the mangrove vegetation in Sundarban are responsible for dynamic eco-system vigorous nutrient cycling both terrestrial and aquatic. The whole eco-system is sensitive to changes in salinity and the continuous cycle of erosion and deposition is affecting the plant communities giving rise to dynamic floristic changes. The plant communities are continuously adjusting to the new conditions.
The total area of the Sunderbans is 9630 sq. km. out of which 4264 sq. km. bears mangrove forest. The area of the Reserve is 2585 sq. km. covering land area of 1600 sq. km. and water body over 985 sq. km.Within this area 1330.12 sq. km. is designated as core area, which was subsequently declared as Sundarban National Park in 1984. An area of 124.40 sq. km. within the core area is preserved as primitive zone to act as gene pool. Within the buffer zone, Sajnekhali Wildlife sanctuary was created in 1976 covering an area of 362.335 sq. km. Considering the importance of the biogeographic region of Bengalian River Forests and its unique biodiversity the National Park area of the Reserve was included in the list of World Heritage Sites in 1985. Whole Sundarbans area was declared as Biosphere Reserve in 1989.
Sundarbans Tiger Reserve provides characteristic type of habitat suitable for animals inhabiting vast tidal swamp area. Because of their intimate association with the estuarine environment, sizeable portion of aquatic and semi-aquatic animal communities are inter-related with the animals inhabiting the land areas. The uniqueness of the habitat is said to have contributed to certain behavioral trends, which are characteristic of Sundarbans tigers only. It is considered that man-eating propensity of tiger in this area is hereditarily acquired over a period of generations in the process of consumption of saline water.
Cheetal, wild boar, rhesus macaque are the main prey species of tiger. Aquatic animals like the crabs and fishes are also eaten by Sundarban tiger which occupies the pinnacle of both terrestrial as well as aquatic food-web. Sundarbans mangrove is the home of a number of endangered and globally threatened species. The Bengal Tiger and the fishing cat are getting effective protection here. .The creeks of Sundarbans form the home of Estuarine Crocodile, Salvator Lizard (Water Monitor), River Terrapin and Horse Shoe or King Crab. This area serves as the nesting ground for endangered marine turtles like Olive Ridley, Green Turtle and Hawk's Bill Turtles. The aquatic endangered mammals like Genetic Dolphins thrive within mangrove creeks close to sea. Number of heronries form here during monsoon as well as during winter. It is home for Trans-Himalayan migratory birds..The Reserve has received effective protection under Project Tiger since its creation. The core area is free from all human disturbances like fishing, collection of wood, honey and other forest produces while in buffer fishing, honey collection and wood cutting are permitted to a limited extent. Protection against poaching and theft of forest produce has been ensured through intensive patrolling by staff in motorboats and launches. The offices and camps are located at strategic points to keep a watch over the area. There exists an effective communication network for protection. Furthermore, the staff is well armed.
Intensive management takes care of the maintenance and improvement of the habitat through eco-conservation, eco-development, education, training and research. Mud-flats on the periphery of the reserve are artificially regenerated with mangrove plants to meet local fuel wood demand and reduce the pressure on buffer. Non-mangrove plantations are also raised along roads and embankments of the fringe area to cater the need of the fringe people.Soil conservation is taken up to stabilize the vulnerable sites. To facilitate the availability of sweet water for animals, ponds have been dug at several places in the forest.The other main activity is controlling man-eating by tigers which existed here since time immemorial and the number of casualties have been reduced from more than 40 to less than 10 per year. This has become possible due to strict control over the movement of the people inside the tiger reserve, alternative income generation and awareness building among people. Use of human-masks, electric human dummies etc. are believed to have also contributed in controlling man-eating by tigers. The straying of tigers into the adjoining villages is a serious problem in the area. Measures like erection of branches of genwa, nylon net fencing at forest side and solar illumination at village side at night have however, helped to reduce the incidents of tiger straying. For rescuing the strayed tiger, method of tranquilization using dart gun is also applied where driving of the tiger to the nearby forest is not possible. The youth of the villages have also been imparted training to enable them to play appropriate role in controlling the straying of the tigers into the habitation.
Sajnekhali has a bird sanctuary and is the only place to have a hotel in this area - the Sundar Cheetal Tourist Lodge. There is a Mangrove Interpretation Centre here.There are watchtowers at Sajnekhali, Sudhanyakhali, Netidhopan, Haldi and a number of other places.Bhagbatpuris a crocodile breeding farm. Tours are organized by the WBTDC. This place is accessible through Namkhana. Both the West Bengal Tourism Department and the West Bengal Tourism Development Corporation organize conducted tours to the Sundarbans by their launches. Bhagabatput is a hatchery of the largest estuarine crocodile in the world.