Epiphytic lichen communities are included in the national Forest Health Monitoring (FHM) program because they help us assess resource contamination, biodiversity, and sustainability in the context of forest health. In 1996, field crews collected lichen samples on 141 field plots systematically located across all forest ownership groups in Idaho. Results presented here are the baseline assessment of the statewide field survey. Seventy-five epiphytic macrolichen species were reported from Idaho. Mean species richness varied significantly from seven to 12 species per plot depending on ecoregion province (p < 0.0001). Four lichen species are reported for the first time in Idaho. Major community gradients in nonmetric multidimensional scaling (NMS) ordination are most strongly related to latitude, elevation, percent forest cover, and lichen species richness. Ecoregion provinces occupy significantly different subsections of n-dimensional species space in multi-response permutation procedures (MRPP, p < 1 x 10­8).