Islam, the state religion, is the faith of 88 percent of the population, almost all of whom adhere to the Sunni branch. Hindus make up most of the remainder, and the country has small communities of Buddhists, Christians, and animists.
A vast majority (98 percent) of the people of Bangladesh are Bengalis and they speak the Bengali language. Minorities include Biharis numbering 250,000 and other tribes numbering about a million, with the Chakma being most numerous in number.
Most of the areas of Bangladesh lies within the broad delta formed by the Ganges and Brahmaputra rivers. Lands are exceedingly flat, low-lying, and subject to annual flooding. Much fertile, alluvial soil is deposited by the floodwaters. The only significant area of hilly terrain, constituting less than one-tenth of the nation's territory, is the Chittagong Hill Tracts in the narrow southeastern panhandle of the country.