“Strangers by Law” examines the various effects and meanings of extramarital birth for illegitimate people in British North America during the eighteenth and early nineteenth centuries. Extramarital birth carried significant legal penalties related to inheritance and other rights of kinship to incentivize formal matrimony, ensure the seamless transfer of private property, and maintain orderly societies more broadly. Within individual families and communities, however, the formal definitions of legitimacy did not always apply, and its effects were felt unevenly across lines of region, gender, race, and class. In the context of North American colonization, moreover, English patriarchal traditions confronted competing notions of kinship held by the various African and Indigenous peoples they encountered, forging alternative frameworks of legitimacy through which some individuals of mixed European, African, and Indigenous descent were able to find influence and opportunity. As the colonial era gave way to the early republic, these opportunities foreclosed even as the legal penalties of extramarital birth diminished for white Americans; however, the social and psychological costs of illegitimacy persisted, carrying profound implications for an individual’s sense of self and interpersonal relationships.Drawing on interdisciplinary methodologies, “Strangers by Law” offers a broad survey of illegitimacy through four case studies. Part One examines the related phenomena of infanticide and child abandonment in early Philadelphia, while Part Two assesses the social consequences of extramarital birth in rural New Hampshire, juxtaposing the strategies of maternal kin with individual acts of re-naming. Part Three analyzes how family and legitimacy became racialized in the context of Anglo-Indigenous encounters and racial slavery, and explores how Carolinians of mixed descent navigated the intersecting categories of race and birth status. The final section consists of a single chapter that reconstructs the personal experiences of two illegitimate individuals as they struggled to understand themselves and their place in the world, while an epilogue reflects on the relationship between extramarital birth, family history, and the silences of the archive.