The concept of the frontier has been central to many recent studies of settler colonialism. In Patrick Wolfe's work, the frontier constitutes the "primal" settler/indigenous binary that structures and belies the ostensible commitment of settler societies to multicultural pluralism. While Wolfe thus calls attention to the role the "frontier binary" plays in the "logic of elimination," he has also criticized the frontier as a representational trope that works to memorialize and whitewash settler invasion. In contemporary historiographic debates in the fields of western and borderlands history within the USA, the concept of the frontier has fared much differently. For US scholars, the very word frontier is irrevocably linked to the legacy of historian Frederick Jackson Turner (1861-1932), who, in his 1893 essay " The Significance of The Frontier in American History," cast the frontier as both a moving line of settlement and the well-spring of American individualism and democracy. Today, US scholars reject Turner's "frontier thesis" as inherently ethnocentric and nationalistic and have largely backed away from the idea that the frontier is the locus of US history and culture. This introductory essay puts the critiques of Turnerian historiography articulated by scholars of the US West and southwestern borderlands into conversation with the rather Turnerian concept of the frontier that informs many analyses in settler colonial studies. Reviewing the work of a broad range of scholars who have offered various alternatives to Turner's narrative of settler expansion, we argue - at a moment when settler colonial studies is poised to make a valuable intervention into the study of settler/indigenous contact and conflict in the USA - that recent historiographic debates in western and borderlands history have much to offer the growing field of settler colonial studies.