Okanagana ferrugomaculata is known from California, Colorado, Idaho, Oregon, and Washington (U.S.A.). It is found in several forested areas of the northwest and has been collected in chaparral. California forests, intermountain forests, and Pacific coastal forests. Sanborn & Phillips (2013) found it associated with lodgepole pine (Pinus contorta) and oaks (Quercus spp.). (Sanborn & Phillips 2013)
