The Sundarbans is the largest mangrove forest or saline woodland in the world. The total area of the Sundarbans is approximately 10,000 square kilometers, shared jointly between Bangladesh and India. The area of the Sundarbans in Bangladesh is 6,517 square kilometers. The Bangladeshi portion of the Sundarbans comprises parts of the Khulna, Satkhira, Bagerhat, Patuakhali, and Barguna districts. As a treasure trove of natural resources, the Sundarbans plays a significant role in Bangladesh's economy. Various types of timber, honey, wax, and fish are harvested from here. The Indian part of the Sundarbans lies in the South 24 Parganas and North 24 Parganas districts of West Bengal.

Rich in biodiversity, the Sundarbans covers 1,874 square kilometers of waterlogged areas formed by a network of rivers, canals, and wetlands. The Sundarbans is known as the habitat of the Royal Bengal Tiger along with a wide variety of birds, spotted deer, barking deer, wild boars, monkeys, jungle cats, porcupines, crocodiles, and snakes, among countless other animal species. The forest is home to about 350 species of plants, 120 species of fish, 270 species of birds, 42 species of mammals, 35 species of reptiles, and 8 species of amphibians. Among the plants that grow in the Sundarbans, the notable ones include the sundari, keora, golpata (nipa palm), gewa, goran, baen, dhundul, and poshur. The forest was named “Sundarbans” after the sundari tree. The only way to enter the Sundarbans is by waterways. Winter is the best time to visit the Sundarbans. In 1997, UNESCO declared the Sundarbans a World Heritage Site.

Designated as a biosphere reserve, the Sundarbans region crosses the India-Bangladesh border and is covered in two articles, each covering a UNESCO World Heritage Site:

• Sundarbans (Bangladesh) — in Khulna Division, Bangladesh
• Sundarbans National Park — in West Bengal, India