This article examines the overlooked synergy between American economic expansion and British imperialism in the late nineteenth century. The established scholarship on American empire in this period focuses on the domestic origins of US expansion into the markets of the Western Hemisphere. This article contends, however, that informal American expansion was shaped by external collaborations with the British World. Between 1865 and 1914, an American “colony” of expatriate businessmen emerged in London that is central to this study. The American “colony” integrated itself within the social and economic networks upon which British imperialism depended and mediated new inter-imperial collaborations. Migrants, knowledge, and investment flowed through these intersections, shaping the geography of American expansion around the global footprint of the British World. A snapshot of the pharmaceutical firm Burroughs Wellcome & Co. spotlights these processes, highlighting the mutual imbrications of the British and American empires and the inter-imperial reciprocities sustaining late-nineteenth century globalisation.
