Data for the study were obtained from 805 African-Americans (10 populations); 922 European-Americans (11 populations); and 555 Hispanics (7 populations). The ethnic origin of each individual was largely self-reported. All samples came from crime laboratories, with the exception of the Louisiana and Cajun samples and the Mexican samples. Population diversity estimates were uniformly high for all subpopulations and for each major ethnic group. Only the Pennsylvania Hispanic group was remarkable with respect to its mitochondrial DNA types, having both six low frequency population specific types (ranging from 1.2-8.6 percent) and three high frequency shared types (10-20 percent each). There was no statistically significant subpopulation heterogeneity present within any of the three major groups at either the subpopulation level or the regional level; however, statistically significant heterogeneity was measured when comparing the three major groups to each other, with the variance component attributable to this large division accounting for 18.6 percent of the total variance. Overall, mtDNA is a satisfactory forensic typing locus within broadly defined African-American, European-American, and Hispanic groups from North America, based on the high diversity estimates and absence of heterogeneity as characterized by SSO typing. 7 tables, 2 figures, and 12 references