The Barrens of the Eastern Highland Rim in south-central Tennessee is a unique area and home to several rare species and plant communities. An arthropod diversity study conducted on Arnold Air Force Base sampled 11 sites that exemplify habitats found within the Barrens. This diversity study documented adults of 37 species of Tenebrionidae (darkling beetles) representing 24 genera; 14 of the 37 species collected are new Tennessee state records. The greatest number of species was collected from Sinking Pond (n = 16), Goose Pond (n = 14), and the Pine site (n = 11), which were all forested sites. No adult darkling beetles were collected in four (Grassland sites 1, 2, and 3 and Maidencane site) of the 11 sites sampled; these four sites are all open and lack a forest component. Of five collection methods that captured tenebrionids, canopy fogging collected the greatest number of species (n = 14), followed by light trapping (n = 13), and under-bark sampling (n = 13). About 50% (n = 84) of all tenebrionid specimens were collected utilizing under-bark sampling, due, in part, to the collection of 24 specimens of Uloma imberbis LeConte and 37 specimens of six species collected solely under bark. This study documented about 28% of the approximate 80 species of Tenebrionidae previously recorded in the literature from Tennessee, while adding 14 species records to the literature. This study helps to characterize the species known from habitats within the Barrens.