In the United States of America, as in other regions of the New World, the colonists imagined that the native peoples were “dying out.” Recent critical studies of this popular and robust narrative neglect to account for its demise. This paper describes the emergence, by the 1870s, of a critique of the “Dying Indian” story that rested on a growing store of population knowledge generated by the United States government. This paper narrates the increasing demographic capacity of colonial authority, starting with Jedediah Morse in the 1820s and noting the use of population data by the Cherokee and by Lewis Cass in the debate about Indian removal in the 1830s. This paper then links the work of Henry Schoolcraft in the 1840s and 1850s to the rise of a reservation system and President Grant's “Peace Policy” in the 1860s, arguing that “statistics” enabled humanitarian policy intellectuals to argue “unsentimentally” for a “civilizing” program. The surveillance capacity of the Bureau of Indian Affairs (BIA) enabled the critique of the “Dying Indian” thesis made by Francis Walker, Selden Clark, and Garrick Mallery in the 1870s which, in turn, contributed to the political success of Senator Dawes's “allotment” policy in the 1880s. This paper concludes by placing the work of these early critics of the “Dying Indian” story in the context of two histories: of U.S. colonial sovereignty and of the discipline of historical demography.