Schadonia saulskellyana is described as new to science based on material from the southern Appalachian Mountains in the eastern United States. The species appears to be endemic to the region and mostly restricted to the bark of conifers. It is particularly abundant and frequent in the imperiled high-elevation spruce-fir forests of the region. The new species is distinguished from its congeners by its corticolous habit, minutely areolate thallus with areoles that erupt into soralia which dissolve the areoles and give the appearance of a leprose crust, epruinose, dark brown-black apothecia with a brown hypothecium, and monosporous asci with large, muriform ascospores. It is also compared with other genera of Pilocarpaceae, particularly Calopadia. Lopadium disciforme, a superficially similar species is also compared to the new species and photographs, as well as a distribution map for eastern North America, are provided for that species.