Bangladesh,[a] officially the People's Republic of Bangladesh,[b] is a country in South Asia. It is the eighth-most populous country in the world and is among the most densely populated countries with a population of nearly 170 million in an area of 148,460 square kilometres (57,320 sq mi). Bangladesh shares land borders with India to the north, west, and east, and Myanmar to the southeast. To the south, it has a coastline along the Bay of Bengal. It is narrowly separated from Bhutan and Nepal by the Siliguri Corridor, and from China by the mountainous Indian state of Sikkim in the north. Dhaka, the capital and largest city, is the nation's political, financial, and cultural centre. Chittagong is the second-largest city and is the busiest port on the Bay of Bengal. The official language of Bangladesh is Bengali while Bangladeshi English is also used in the government and official documents alongside Bengali.

Bangladesh forms the sovereign part of the historic and ethnolinguistic region of Bengal, which was divided during the Partition of India in 1947 as part of a Muslim union with Pakistan, which it separated from in a bloody independence war in 1971.[23] The country has a Bengali Muslim majority. Ancient Bengal was known as Gangaridai and was a bastion of pre-Islamic kingdoms. Muslim conquests after 1204 heralded the sultanate and Mughal periods, during which an independent Bengal Sultanate and a wealthy Mughal Bengal transformed the region into an important centre of regional affairs, trade, and diplomacy. After the Battle of Plassey in 1757, the maximum extent of British Bengal stretched from the Khyber Pass in the west to Singapore in the east.[24][25] The creation of Eastern Bengal and Assam in 1905 set a precedent for the emergence of Bangladesh. The All India Muslim League was founded in Dhaka in 1906.[26] In 1940, the first Prime Minister of Bengal, A. K. Fazlul Huq, supported the Lahore Resolution. Before the partition of Bengal, a Bengali sovereign state was first proposed by premier H. S. Suhrawardy. A referendum and the announcement of the Radcliffe Line established the present-day territorial boundary.