Sonoma Mountain Road West is only accessed from the east side of Sonoma Mountain (there is a Sonoma Mountain Road West that is just east of Petaluma, but that road does not connect to Sonoma Mountain Road East). As with so many Sonoma County climbs, this ascent is on a narrow rugged road that offers exceptional views of vineyards along much of its route. The crux stretch of this climb is 4/10's of a mile beginning at about the 1/3 mile mark which at ~10% average grade strains the quads immediately. Thereafter, the grade is manageable and the views at times exceptional.
Mt. St. Helena
Traffic/Roadway Surface: The roadway is in poor to fair condition and very narrow and there is a fair amount of traffic (well, comparatively for rural Sonoma County roads). Caution should be used descending due to loose gravel, sharp turns, rough roadway and uphill traffic