We used to go to one in Sonoma County. I would have thought these were pretty common but apparently it was one of only 6 listed in California on the wikipedia p

We used to go to one in Sonoma County. I would have thought these were pretty common but apparently it was one of only 6 listed in California on the wikipedia page https://en.wikipedia.org/wiki/List_of_gravity_hills https://en.wikipedia.org/wiki/List_of_gravity_hills