This paper unites quantitative and qualitative data from the College Social Life Survey (n = 732) to describe and explain patterns of racial homophily in undergraduate sexual/romantic relationships at an elite university, a closed social setting. It expands the literature on interracial romantic unions by comparing homophily in hookups (uncommitted sexual interactions), dates, and long-term relationships. Although this population embodies many characteristics associated with greater racial mixing (youth, education, status equality, geographical proximity, racial diversity, independence from family), racial homophily is still strongly evident. Variation in levels of homophily among relationship types and among racial groups is explained by differences in desired homophily, social network segregation, and participation in formal race-based student organizations. Black students are particularly socially isolated.