This article scrutinises the ramifications of population movements between India and Pakistan in and after 1947 in one particular border district in West Bengal. Information from census reports of pre-independent and independent India and Pakistan allows detailed examination of micro-level cross-border migrations, showing how the relocation of populations completely recast the religious and demographic contours of this border district. Within just four years, the Muslim-majority district of Nadia turned into an overwhelmingly Hindu-majority district through this two-way population movement. Contrary to popular perceptions, which stress the unidirectional pattern of migration on the eastern side of India, this article brings to the fore a hitherto unknown facet of partition migration. www.researchgate.net/publication/275454908_Population_Movements_in_West_Bengal_A_Case_Study_of_Nadia_District_1947-1951