This article reexamines the legacies of Argentina's Conquista del Desierto (Conquest of the Desert, 1878–1884) by analyzing these expansionist campaigns through the lens of the ideology of manifest destiny in the United States. Using the racial, religious, and nationalist concepts constructed in the United States as part of the broader discourse of manifest destiny, I examine both the history of the Conquest of the Desert, focusing on how official narratives from the period created and sustained a notion of alterity, and more recent controversies over claims of "ownership" of the pampas and Patagonia, especially as they relate to ideas of originality and autochthony. The article draws on first-person accounts of the military expeditions of the late nineteenth century and situates these descriptions using literatures on whiteness, ethnicity, and nationalism in Argentina and the United States. I suggest that as a physical, discursive, and even religious space, the frontier became a critical site for national production in both countries. Further, "divine providence" played an integral role in justifying both the need for and the moral imperative of the state's expansionism. This combination of religion and territoriality raises questions about the place of the Indian/el indio in the future imagined nation. I argue that reading these cases together provokes new conversations about historical perspectives on the Conquista and contributes to debates on indigenous autochthony and authenticity and to the broader discussion of understandings of Argentine nationalism.