Found only in the large tributaries of the Cumberland River below Cumberland Falls. The mainstem and large tributaries of the Big South Fork and Rockcastle rivers are home to the largest populations. The Buck Creek population was considered extirpated by Shepard & Burr (1984), but several specimens have been collected in recent years, suggesting the species has made a comeback in the stream. The Red and Stones river populations of the E. cinereum complex were considered extirpated by Shepard and Burr (1984) and despite sampling in these drainages for this and other projects by the authors and many other researchers, we have no evidence to contradict this assertion. The status of populations in the Obey and Roaring rivers was considered unknown by Shepard & Burr (1984) due to absence of the species from collections in these drainages since the early 1970s. Sampling in these rivers for this and other studies by the authors and other researchers has not yielded specimens, suggesting these populations are extirpated. However, given the recent rediscovery of E. cinereum in the Elk River after a 30-year absence, it is possible that these populations may persist in low numbers in what appears to be suitable habitat for the species (Ref. 89958).