We conducted extensive sampling of the subterranean termites in a portion of Charles Towne Landing State Historic Site in Charleston, South Carolina. Samples of at least 20 workers each were collected from 64 collection points, mainly from natural wood debris close to a marsh. Samples were identified to species either using established keys (for C. formosanus) or by RFLP analysis of the COII gene (for Reticulitermes spp. designations). Twenty workers from each collection point were genotyped at eight microsatellite loci. Collection points that were not significantly differentiated from each other were considered part of the same colony. We found a total of 48 colonies. R. flavipes was the most abundant species present (n=18), followed by R. hageni (n=17), R. virginicus (n=7), and C. formosanus (n=6). Colonies of R. flavipes and R. hageni were fairly localized, being present at only a single collection point, whereas those of R. virginicus and C. formosanus were more expansive with multiple collection points separated by distances up to 120 m. The genetic structure of colonies was remarkably uniform across species, with the majority of colonies (range=72-88%) possessing worker genotypes consistent with being simple families headed by monogamous pairs of reproductives and the remainder of the colonies being extended families (neotenic-headed families descended from simple families).