A review of the crustose lichen genus Rinodina in Great Smoky Mountains National Park is presented. Seventeen species are reported from the study area, of which three represent new reports (R. bullata, R. excrescens, and R. oxydata) and one is described as new to science (R. brodoana). Based on current collections, the new species is restricted to old growth hardwoods and occurs at middle to low elevations. Also based on collections information, two species (R. brodoana and R. chrysomelaena) are proposed to have IUCN Red List ranks of critically endangered. We discuss the increasing significance of middle to low elevation habitats in this biodiversity hotspot. All 17 species reported from the study are illustrated, their biogeographic patterns and ecologies are discussed, and maps showing revised North American distributions, are provided. A key to the 21 species of Rinodina known to occur in the southern Appalachian Mountains is also provided.