We are currently performing system maintenance on the registration system. We will be back up and running shortly.

We want to thank all who participated in the 25 Hours of Thunderhill in November 2023. We had a great time hosting this event for the 20th running and are always thrilled to see our returning teams and the new ones that join us for this epic race.
Based on many factors, we have decided not to run the event in 2024, and plan to return with an even more robust event in 2025. Thank you for your continued support. If you have any questions, please feel free to reach out.
We look forward to hosting you again for The 25 Hours of Thunderhill in 2025.

– Jerry Kunzman


Everything You Wanted to Know About The USAF 25 Hours Of Thunderhill Presented By Hawk Performance

The NASA 25 Hours of Thunderhill is the longest closed-course endurance race in North America. Begun in 1998 as the Timex 12 Hours of Thunderhill, the race expanded to 25 hours in 2003, and has since evolved to become known as one of the most grueling endurance races in the nation, attracting amateur and professional sports car drivers from around the world. From the challenging track and the winter weather to the speed differentials among all the cars involved, nothing about the 25 Hours of Thunderhill is easy. Almost anyone can enter, but if you want to win, you had better bring your best. 


Questions and Answers to Feed Your Curiosity

The 25 Hours of Thunderhill is held at Thunderhill Raceway Park in Willows, Calif.

If there are no weather delays, the race begins at 11 a.m. Saturday and ends at noon Sunday

Most teams have settled on a range of three to six drivers to run the event.

Yes, but rookies may only drive during daylight hours, so if you want to run the whole race, you must have drivers with regular competition licenses to handle night duties.

Yes. The 25 Hours of Thunderhill requires a team effort, and that means a full crew, professional or volunteer. You’re going to need people to do everything from fueling, servicing and repairing the car to forming race strategy and keeping everyone rested and fed.

Everything from the Mazda Miata and BMW 3-series cars compete alongside quarter-million-dollar prototypes. You can run what you brung or bring as much car as you want. There is a class for every vehicle except for open-wheel cars.

Go to the NASA Events page and get signed up when registration opens midsummer and before it closes in late November.


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NASA 25 Hours of Thunderhill Contacts

25 Hours of Thunderhill
Jerry Kunzman
Region: California-Northern
Title(s): Regional Director
Series: 25 Hours of Thunderhill