The literature on ethnic fractionalization and conflict has yet to be extended to the American past. In particular, the empirical relationship between racial residential segregation and lynching is unknown. The existing economic, social, and political theories of lynching contain implicit hypotheses about the relationship between racial segregation and racial violence, consistent with more general theories of social conflict. Because Southern lynching occurred in rural and urban areas, traditional urban measures of racial segregation cannot be used to estimate the relationship. Earlier analysis has analyzed the relationship between lynching and racial proportions, a poor proxy for racial segregation. We use a newly developed household-level measure of residential segregation (Logan and Parman 2017) that can distinguish between the effects of increasing racial homogeneity of a location and the tendency to segregate within a location given a particular racial composition to estimate the correlation between racial segregation and lynching in the southern counties of the United States. We find that conditional on racial composition, racially segregated counties were much more likely to experience lynchings. Consistent with the hypothesis that segregation is related to interracial violence, we find that segregation is highly correlated with African American lynching but uncorrelated with white lynching. These results extend the analysis of racial/ethnic conflict into the past and show that the effects of social interactions and interracial proximity in rural areas are as important as those in urban areas.