This dissertation investigates race as a determinant of health trajectories for immigrants to the United States. Previous research suggests that integration into U.S. society can be detrimental to the health and mortality outcomes of many minority immigrant groups. Popular explanations for post-migration health changes have focused on individual-level mechanisms, such as behavioral changes associated with acculturation. I use multiple sources of data and a variety of quantitative methods to situate these changes in a context of racial inequality for three migrant groups. In my first case, I draw on historical data collected from the Vital Statistics of the United States and the U.S. Census to analyze the changing health trajectories associated with European immigrants’ transition from marginalized minorities to members of the white majority in the early 20th century. My second case draws on restricted-use data from the National Survey of American Life to test how interpersonal and institutionalized racial discrimination influence health patterns of black immigrants from the Caribbean. In my third case, I use population-level birth data from New York City (2000-2010) to investigate changes in birth outcomes associated with elevated anti-Muslim sentiment after the attacks of September 11, 2001. Taken together, these cases demonstrate how racial formation in the United States shapes patterns of post-migration outcomes. I find that marginalized European immigrants exhibited patterns of worsening mortality trajectories, but the overall gap between European immigrants and native-born whites narrowed as racial categories were redefined in the early 20th century. This pattern of intergenerational health improvement contrasts with the segmented trajectories of contemporary Caribbean black immigrants, whose health is shaped by experiences of both interpersonal and institutionalized racism. Similarly, rates of low birth weight births increased for Middle Eastern and Asian Indian immigrants in the decade after the attacks of September 11, 2001, likely due to increased experiences of discrimination. By tying health trajectories and outcome disparities to the construction and stratification of racial boundaries, I advance theory about the "upstream" social causes of health and illness and develop a framework for analyzing the sociohistorical formation of health disparities.