Thunderhill Raceway Park

Thunderhill Raceway Park is a road racing course located 7 miles (12 km) west of Willows, California on Hwy 162. The course is a fast series of twists and turns with minor elevation changes. Thunderhill is owned and operated by the San Francisco Region of the SCCA. It is host to many motorports events for cars and motorcycles. The SCCA uses Thunderhill for its automotive race competitions. The Northern California Chapter of the AFM runs several motorcycle races there every year. A large number of automotive commercials have been filmed at the track.

The standard road course at Thunderhill Park is a 3.0-mile (4.83-km), 15 turn course, however the track is configurable and event organizers can configure the course as they see fit.

Thunderhill is the site of the longest automobile race in the United States; the 25 Hours of Thunderhill. The race is held annually during the first weekend in December and is sanctioned by NASA (National Auto Sport Association).

The track was financed by a $50 surcharge on every entry to a San Francisco Region race, with the goal of building the track without ever needing a loan. Hundreds of volunteers put in many thousands of hours of work. First the land was purchased, then first 1.9 miles segment of the track was graded and paved. Paving the paddock and the entrance road waited until after the track was prepared to the highest level.