Abstract By centering Indigeneity, specifically O'odham presence, sovereignty, and land at the site of the U.S.–Mexico border, I argue that the U.S.–Mexico border, the Department of Homeland Security, and U.S. immigration law are ongoing, settler colonial, and imperial formations of U.S. empire. Further, this paper investigates the settler process of racialization, specifically the construction of "illegal alien," and how, at the border, this racial category is imposed onto, and erases, Indigeneity. I argue that while racialization at the border focuses on criminalizing illegal crossings, it also eliminates Indigenous ontologies of migrants and immigrants, and eclipse land-based Indigenous presence and sovereignty. Through content and discourse analysis, and archival research, I critically read O'odham Indigenous critique of the border and immigration policies against U.S. government documents to show that the settler racialization process of undocumented border crossings is foundationally one of Indigenous erasure and genocide. The aim of this paper is to broaden the scope of critique via an analytic of Indigeneity in the realms of the academy, advocacy work, organizing, activism as related to the U.S.–Mexico border and U.S. immigration.