Aspergillus fumigatus is the primary causal agent of the respiratory illness aspergillosis. Resistance to triazoles has been developing as a result of their use in clinical and agricultural environments. The goal of this research is to characterize triazole resistance in A. fumigatus, particularly in the United States. An extensive review of literature found that two cyp51A alleles were found to be primarily responsible for pan-azole-resistant phenotypes throughout the world: TR34/L98H and TR46/Y121F/T289A. These alleles and others were found in A. fumigatus primarily isolated from soil, air, and plant debris. Eight types of commercial products were surveyed to identify azole-resistant A. fumigatus in the United States. The majority of pan-azole-resistance was found in strains isolated from compost and flower bulbs. DAPC and cluster analysis revealed that 3 clusters are formed from these isolates based on the presence of a cyp51A tandem repeat and the T248N/E255D allele.