It is part of the Sundarbans on the Ganges Delta, and adjacent to the Sundarban Reserve Forest in Bangladesh. The delta is densely covered by mangrove forests, and is one of the largest reserves for the Bengal tiger.

Sundarban, the largest delta in the world, consists of 10,200 sq km of Mangrove Forest, spread over India and Bangladesh. The part of the forest within Indian Territory is called Sundarbans National Park and is in the southern part of West Bengal. The Sundarbans cover an area of 38,500 sq km, of which about one-third is covered by water/marsh. The forest has a large number of Sundari trees. Sundarban is world famous for the Royal Bengal tigers.
Location of Sundarban National Park:
Sundari Trees at Sundarban National Park:
Fauna of Sundarban National Park:
Sundarban National Park: facts at a Glance
1. The Sundarban National Park is a National Park, Tiger Reserve, and a Biosphere Reserve in West Bengal, India.
2. The present Sundarban National Park was declared as the core area of Sundarban Tiger Reserve in 1973 and a wildlife sanctuary in 1977. On 4 May 1984 it was declared a National Park.
3. It was declared a UNESCO World Heritage in 1987 and the Sundarbans region as a whole was declared a Biosphere Reserve in 1989.
4. Sundarban is the largest delta in the world. It comprises of 10,200 km2 of Mangrove Forest, spread over India and Bangladesh.
5. The Indian part of the forest within Indian Territory is called Sundarbans National Park which is situated in the southern part of West Bengal.
6. The Sundarbans cover an area of 38,500 sq km, of which about one-third is covered by water/marsh.
7. The forest has a large number of Sundari trees and it is said that the forest got its name from these trees.
8. The delta is one of the largest reserves for the Bengal tiger.
9. It is also home to a variety of bird, reptile and invertebrate species, including the salt-water crocodile.
10. It is the natural habitat of many other wild animals like jungle fowl, giant lizards, spotted deer, wild boar, crocodiles, etc. Siberian ducks set up residence during their migratory season. Sundarbans is also home to endangered species like Batagur baska, King Crabs and Olive Ridley Turtles.
11. There are around 74 royal tigers in Bengal in estimation of 2015.

It is famous for being the world largest delta made by ganga and bhramputra in Bey of Bengal . Its name come from the sundari trees found in this delta. This Delta contain mangrove forest .