On 14 August 1947 the Indian sub-continent was partitioned, and Pakistan was carved out of the north-western and north-eastern parts of British India. The territories of Baluchistan, North West Frontier Province, Sind, and the western part of the Punjab constituted its west wing with an area of 365,529 square miles and an approximate population of 33 million, and the major portion of Bengal plus its contiguous district of Sylhet from Assam constituted its east wing with an area of 55,126 square miles and an approximate population of 42 million, the two wings being separated by over a thousand miles of Indian land mass. West Pakistan (now Pakistan), like most of west Asia, consisted of semi-arid plains and rugged mountains. About one-fifth of its land was cultivated. The distribution of population was highly uneven, and was determined primarily by the availability of water. East Pakistan (now Bangladesh) consisted of much more densely and evenly populated low-lying deltaic plains which, like most of south-east Asia, were green with abundant rainfall.

In both area and population, Pakistan at birth was larger than any European country except Russia, and was the seventh most populous country in the world. In spite of low per capita income and traditional peasant agriculture, Pakistan with a population of 75 million was a sizeable economy. But the conjoining of a pair of widely separated and fundamentally diverse fragments split off the British Raj in India to form one Pakistan based on Moslem religious fraternity in spite of potentially irreconcilable cross-currents of political, economic and cultural interests of the two wings, was a unique and unusual experiment in statecraft.