Forty-five years after racial residential segregation was outlawed, we might expect America's neighborhoods to be fully integrated. Segregation, however, persists. Across five studies, I explore how the prevalence of segregation can fuel its own perpetuation by setting powerful descriptive norms. In Study 1, when participants were exposed to information about high rates of residential segregation in the United States, they conformed and expressed significantly stronger preferences for same race neighbors than those exposed to low rates of segregation. Further, this normative information changed individuals' conceptions of race. In Study 2, learning that segregation is common, rather than uncommon, caused participants to endorse a more essentialized or biological conception of race. This conception of race as biological was itself significantly associated with preferences for same race residential contact in Studies 3 and 4. Further in Study 5, I demonstrated that biological conceptions of race can cause preferences for racially segregated neighborhoods. This work illustrates that physical arrangements of racial groups within residential spaces can shape preferences for social contact with members of different races and can signal how essential race is as a category.