Ties among persons of different backgrounds, when such ties act as social bridges, play a vital role in diverse societies—expanding identities, opening insular communities of interest, containing intergroup conflicts, and reducing inequalities. Using a phone survey of 29 city-regions matched with census data, this study analyzes predictors of interracial friendships for Whites, Blacks, Asians, and Hispanics, with single- and multilevel path models. Results underscore the social significance of the workplace and of civic involvement. Those who report ties to other races tend to be “joiners,” in the broad sense: Involvement in nonreligious groups, socializing with coworkers, and having more friends are robust predictors for all racial groups. These are strongly associated with each other and with higher socioeconomic status, highlighting a powerful class dimension to accessing intergroup ties. But macro-level opportunity for contact (metro-level racial makeup) dominates the variation in friendship exposure patterns for Whites, whereas associations and other “substructures” are more predictive for minorities. Consistent with immigrant assimilation theory, among minorities, sharing neighborhoods with Whites remains an important—and apparently unique—social marker for the personal relationships of Blacks.