The social, economic, and political history of the Brahmaputra-Meghna River Basin—encompassing all of what is now Bangladesh—was shaped over many centuries by the slow but steady migration of people from west to east across the Gangetic Basin. Peasants came in search of land to farm, speculators came to control farm production, and military men came to control over strategic sites of political authority, where they could profit from, if not control, profits from farming and trade overseas into the Bay of Bengal and inland over mountains into Burma and China. All these migrant settlers entered a land-and-waterscape dominated by tribal groups engaged in hunting, fishing, shifting cultivation, and trade, who never bowed down to any Gangetic ruler, who never used metal coins that symbolized Gangetic authority, and who conducted commercial exchange only with cowrie shells, which traveled routes across the Indian Ocean from the Maldives and across Bengal through the mountains into China. Records of the East India Company provide our first close-up view of the interaction migrant power and mobile social life in this region at the end of the eighteenth century.