Data from field trips and a survey of herbarium specimens was used to determine relative abundance of the ten known species of Rhododendron (Ericaceae) in each county of South Carolina. All counties were documented to contain at least one species. The western-most mountainous and upper piedmont counties of Oconee, Pickens, Spartanburg, and Greenville were found to have the greatest richness and the greatest number of documented populations. Of the four counties with only one documented species, three are in the piedmont and one in the coastal plain. Species found in the greatest number of counties were Rhododendron canescens. R. viscosum, and R. periclymenoides. Meanwhile species known from the fewest number of counties were R. calendulaceum. R. flammeum. R. maximum, and R. arborescens. Taxonomic keys were generated for species identification, the first key for spring and early summer flowering material, and the second for summer and fall vegetative or fruiting material.