Diversification of the United States population over the past 45 years has sparked a debate about the contemporary racial structure. Some theorize Latino and Asian immigrants will eventually integrate into the White community, like the European immigrants before them. Others suggest their classification as “people of color” means they will integrate into the Black community. Still others theorize the United States is moving towards a three-tiered racial hierarchy. Racial residential segregation has been demonstrated to be an influential factor in reproducing racial classifications. Yet the use of residential distribution data to test hypotheses of racial structure has been limited because, I argue, segregation indexes are based on particular racial structures, none of which effectively capture multiple tiered hierarchies. Thus, this paper investigates the contemporary racial structure manifested through residential distribution by comparing computer simulations of hypothesized distributions to the observed distributions of Asians, Blacks, Latinos, and Whites in all census tracts in the United States in 1980, 1990, 2000, and 2010. Finding that residential segregation contributes to the mounting support for Bonilla-Silva’s theory of a three-tiered racial hierarchy, this paper argues that future research on residential segregation needs to utilize an index that effectively measures segregation in multigroup populations. Through an evaluation of the most widely utilized indexes and conceptions of segregation, this paper introduces the Summary Index of Multigroup Segregation (SIMS), which builds off the Segregation Index to give an overall measure of segregation similar to Theil’s Information Index but that can be compared across populations with different group compositions. The SIMS calculates the proportion of the total population that would need to move for the area to be completely integrated. If commonly adopted, the SIMS can enable researchers to compile studies to further investigate the factors contributing to multigroup segregation and the implications of multigroup segregation.