Between 1850 and 1930, demographic upheaval in the United States was connected to reorganization of the racial order. Socially and politically recognized boundaries between groups shifted, new groups emerged, others disappeared, and notions of who belonged in which category changed. All recognized racial groups—blacks, whites, Indians, Asians, Mexicans and others—were affected. This article investigates how and why census racial classification policies changed during this period, only to stabilize abruptly before World War II. In the context of demographic transformations and their political consequences, we find that census policy in any given year was driven by a combination of scientific, political, and ideological motivations.
Based on this analysis, we rethink existing theoretical approaches to censuses and racial classification, arguing that a nation's census is deeply implicated in and helps to construct its social and political order. Censuses provide the concepts, taxonomy, and substantive information by which a nation understands its component parts as well as the contours of the whole; censuses both create the image and provide the mirror of that image for a nation's self-reflection. We conclude by outlining the meaning of this period in American history for current and future debates over race and classification.