Blastomycosis, a well-recognized human mycosis caused by the soil-dwelling fungus B dermatitidis, is an endemic infectious disease with an interesting geographic distribution in North America. The highest blastomycosis prevalences in the United States are in Mississippi, where it is a reportable disease, followed by Arkansas and Kentucky.10 Chapman and colleagues4 previously described annual incidence rates for blastomycosis at more than five cases per 100,000 population in certain hyperendemic counties in Mississippi, which included low-lying coastal plain regions with sandy, low-pH soil, decaying organic matter, and high humidity. Other authors3,6,11 have also correlated high incidence rates of blastomycosis in geographic settings typified by low elevation, sandy acidic soil, and proximity to waterways. For the state of Tennessee, it could be hypothesized that significant rates of blastomycosis might be documented in the western portion of the state, which borders Arkansas, Missouri, Mississippi, Kentucky, and the Mississippi River, whereas the disease might be uncommon in the mountainous northeast section of the state, which includes the southern Appalachian mountains. In support of this hypothesis are publications by Chick et al,12 who, in 1956, described the epidemiologic aspects of 86 patients with blastomycosis who had been admitted to Memphis, TN, hospitals over a 32-year period, and the work of Furcolow et al5 and Duttera and Osterhout,6 who commented on the rarity of blastomycosis among the populations inhabiting the mountainous areas of eastern Kentucky and western North Carolina, respectively. Interestingly, our previous report7 of 72 cases of blastomycosis from the northeast Tennessee region for the period from 1980 to 1995 stands in contrast to the perception that blastomycosis is uncommon in mountainous areas. In comparison to Memphis, in the far western part of the state, the Tri-Cities geographic region is more rural with a location adjacent to the Appalachian mountains (elevation in the Tri-Cities area, 1,208 to 1,635 feet above sea level; elevation in the nearby mountains, approximately 4,000 to 6,000 feet), the winter climate is harsher, and the soil varies from rocky to red clay in valleys to sandy in river and stream terraces.