Sunderban Tiger Reserve is a part of the Sunderban delta mass in South 24 Pargana district of West Bengal. It is land-locked and tidal channels divide the entire tiger reserve into small and big islands. The green part is the forest area outside the tiger reserve and is known as the 24 Pargana Forest Division. The pink shaded area is Sajnekhali Sancturary, the blue part is the Sunderban National Park, and the rest of the islands between the sanctuary and the national park and east of the sanctuary together form the tiger reserve. The tiger reserve together with the 24 Pargana Forest Division and villages along their fringes form Sunderban Biosphere Reserve. Sunderban is a World Heritage Site.