The United States's collection of race data in Census 2000 and the 2010 Census provides a historical and landmark opportunity to compare results from two decennial censuses on the distributions of people reporting multiple races in response to the census. This research provides insights on the number of people who reported more than one race and details on various multiple-race combinations (e.g., White and Black or African American; White and Asian; White and American Indian and Alaska Native). This article presents analyses of the Two or More Races population and the largest multiple-race groups at the national and state level. The results inform data users and the public about an evolving portrait of the multiple-race population in the United States. (Contains 13 tables, 3 figures, and 1 note.)