In the 1950s and 1960s, translocation projects reintroduced black bears (Ursus americanus) from Minnesota and Manitoba to Arkansas and Louisiana. Today, several geographically disconnected populations exist in Arkansas and Louisiana, but their origins are unclear. Some populations may represent a separate subspecies, U. a. luteolus, which is federally protected. We characterized 5 microsatellite loci in 5 isolated populations in Arkansas and Louisiana and compared them with genotypes from Minnesota. Our data indicate that bears of the Ozark and Ouachita mountains of Arkansas, an inland area of Louisiana, and those of Minnesota are similar in overall genetic diversity and allele frequencies, consistent with these populations being wholly or mostly descended from bears from the reintroduction programs. In contrast, bears from southeastern Arkansas and the coastal region of Louisiana genetically are more restricted and homogeneous. Because they exhibit a limited set of genotypes found in the other black bear populations, they represent isolated fragments of a single North American black bear population. Furthermore, genetic distance estimates indicate that the bears in southeastern Arkansas are more genetically distinct from bears in Louisiana, which are currently federally protected.