Yes. Extreme western Riverside County. And you are correct on the mountain range as well. I quess I am going to find out for myself soon enough. I have never seen one in the field, so I am looking foreward to researching this area. Already noticed that the Striped Racer (which is abundant in the San Gabriel Foothills) is uncommon here. However Coachwhips seem much more plentiful in these parts.