Thunderhill Raceway Park, Racing Circuit

Thunderhill Raceway Park sits on former farmland near Willows in Northern California and was conceived as a track built for racers by racers. It was created by the San Francisco Region of the SCCA, which grew frustrated through the 1980s with securing race dates at Sears Point and Laguna Seca and, with Riverside closing, resolved to build its own venue. Plans were drawn by Steve Crawford to exploit the natural topography, including a corner reminiscent of Laguna Seca's Corkscrew known here as The Cyclone, and the track opened on Halloween 1993 with a 1.9-mile layout. A west extension in 1995 brought the full course to nearly three miles and allowed the circuit to be split so east and west sections could run simultaneously. The venue is famously busy, hosting around a thousand events a year across its road courses plus motocross and rallycross tracks. Its signature event is the 25 Hours of Thunderhill, run by the National Auto Sport Association and for years the longest endurance race in the world, alongside budget-racing 24 Hours of Lemons rounds. In 2014 a new west course was blasted through a rocky ridge and joined to the original, creating a five-mile combined circuit of 27 undulating turns nicknamed the 'Thunderschleife' for its Nordschleife-like character. That combined layout is the longest permanent road course in the United States. Constant expansion under CEO David Vodden has kept the facility evolving since its earliest days.

Operated by: San Francisco Region SCCA (SF Region Properties Inc)