A disjunct stand slightly north of the Umpqua River in southwestern Oregon has been reported as the northernmost limit of tanoak's natural range. The general northern limit of tanoak in the Coast Ranges, however, is farther south in the Coquille River drainage. Its eastern limit in Oregon extends from west of Roseburg to Grants Pass, and then southwesterly into the Applegate River drainage. Tanoak's range stretches southward through the Coast Ranges in California to the Santa Ynez Mountains north and east of Santa Barbara, CA. The range also extends northeastward from the Humboldt Bay region to the lower slopes of Mount Shasta, then intermittently southward along the western slopes of the Sierra Nevada as far as Mariposa County (7). In the Sierra Nevada, tanoak is most common between the Feather and American Rivers.
-The native range of tanoak.