The Sundarbans is the single largest mangrove forest in the world located in the southern part of Bangladesh sharing one-third part with India. It has been declared as a UNESCO world heritage site in 1997 and designated a Ramsar site in 1992. The forest lies a little south to the Tropic of Cancer between the latitudes 21º30´N and 22º30´N, and longitudes 89º00´E and 89º55´E. The forest consists of about 200 islands, separated by about 400 interconnected tidal rivers, creeks and canals. The forest part is estimated to be about 4,110 km², of which about 1,700 km² is occupied by waterbodies as if it is a water-logged forest. The forest meets the Bay of Bengal to the south; it is bordered by the Baleswar River to the east and to the north there is a sharp interface with cultivated land. The Sundarbans' floor varies from 0.9 m to 2.11 m above sea level.
The word ‘Sundarban’ is a Bengali term, means “beautiful forest”. According to different sources that the name Sundarban may have been derived either from the Sundari trees, the main beauty of this forest or from the colloquial term of Samudraban (Sea Forest). The history of the Sundarban area can be traced back to 200–300 AD. A ruin of a city built by Chand Sagar has been found in the Baghmara Forest Block. During the Mughal period, the Mughal Kings leased the forests of the Sundarbans to nearby residents. Many of the buildings which were built by them later fell to hands of Portuguese pirates, salt smugglers and dacoits in the 17th century. Evidence of the fact can be traced from the ruins at Netidhopani and other places scattered all over Sundarbans.
About 200 years back, the Sundarbans was measured as around 16,700 sq km of which about one-third disappeared in last two centuries. Since the partition, Bangladesh received about 2/3 of the forest.