Aspen fleabane is widely distributed throughout western North America. In Canada, it occurs in British Columbia and Alberta. In the United States it occurs in western South Dakota and all states to its west, except California. However, there is a population in Baja California that is disjunct from the nearest southernmost populations in Arizona (Nesom 2006). Aspen fleabane is particularly common in the Great Basin and Intermountain regions (Hermann 1966).