Three subspecies of Rosa carolina L. (Rosaceae) are recognized in eastern Canada, the United States, and Mexico, including one change in combination and status and a new subspecies, respectively: R. carolina subsp. subserrulata (Rydberg) W. H. Lewis and R. carolina subsp. mexicoensis W. H. Lewis. Rosa carolina subsp. subserrulata occurs commonly in the western range of the species centered in the Ozark Plateau and adjacent areas, north in the midwestern United States to eastern Lake Superior in Canada, and infrequently to the eastern ranges of the Appalachian and Allegheny Mountains, while R. carolina subsp. mexicoensis is a southern disjunct subspecies of the Sierra Madre Oriental in northeastern Mexico. Two nothospecies are described for putative hybrids: R. ×medioccidentis W. H. Lewis is recognized between R. carolina and R. arkansana Porter in the midwestern United States, and R. ×novae-angliae W. H. Lewis between R. carolina and R. virginiana Miller in the eastern United States region of New England. Synonyms are provided for appropriate subspecies and hybrids. Two lectotypes are designated here, and representative exsiccatae or paratypes are given for the new subspecies and nothospecies. The following names are lectotypified: R. rudiuscula Greene and R. serrulata Rafinesque.