In the second half of the nineteenth century, American Presbyterian “home” and “foreign” missions developed parallel and mutually reinforcing policies towards freed slaves in Egypt, Sudan, and the U.S.A. as well as towards Egypt's indigenous Christians, the Copts. Yet the racial ideologies and social hierarchies of these three countries reflected distinct historical trajectories of migration and conquest. In the Nile Valley, American missionaries struggled to understand, address, and sometimes revise Egyptian and Sudanese social hierarchies, which they found alternately idiosyncratic or unjust. This essay conjectures that these interactions, in the long run, induced the Nile Valley missionaries to confront the lingering injustices and incongruities in American social hierarchies, particularly in the mid- to late twentieth century. In this way, the “foreign” mission experience had a backflow for missionaries and their church by raising questions about American racial orders and by strengthening a commitment to civil rights and social justice agendas.