This Article addresses a different sort of legal transplant — one in which outside legal doctrines are imported in order to be cabined, treated as normative counterpoints, and identified as the legal other. Legal primitivism is a kind of anti-transplant. It heightens the persistent differences between a dominant legal system and its understanding of primitive rules. An often ignored legal literature depicting legal primitivism emerged in the second half of the nineteenth century and in the early twentieth century. Mapping the differences between America’s modern legal system and its antecedents, this immense literature, which included works by OliverWendell Holmes, James Coolidge Carter, and John Henry Wigmore, described an archaic legalism which sometimes belonged to tribal societies, and sometimes was simply conjured out of thin air. Exploring the project of constructing geographies of legal knowledge assists in our understanding of American law in a period of significant change. What elements of primitive law were valorized? Which were seen as archaic or repugnant? And what was the purpose of constructing a legal doppelgänger? By examining these cultural negotiations, and holding legal primitivism up as a mirror to modern law, it is possible to uncover the anxieties of legal modernism.