A fun race track in Willows, California. Thunderhill is a 3 mile long race track that can be configured in a variety of ways, and can be split into two tracks (1.8 and 1.2 miles each) to support two events at once.
Thunderhill is a great place for beginners, because it has very safe runoffs around the entire track. If you get too excited and go off course, odds are that the worst that will happen is a very, very dirty car. Of course, racing is inherently dangerous and it's quite possible to roll a car, hit a k-wall, or have other catastrophic issues. However, it's much less likely at Thunderhill than at most race tracks.
Thunderhill is owned and operated by the San Francisco Region of the SCCA.