What distances are available for this event?
- →100K trail race starting at the Lake Sonoma Visitor Center area
- →50K trail race starting at the Lake Sonoma Visitor Center
- →Trail Sisters Women's Half Marathon, a 13.1-mile point-to-point race starting at the Lone Rock Trailhead
What are the race cutoff times?
- →100K: 19 hours
- →50K: 11 hours
- →Trail Sisters Women's Half Marathon: 5 hours total; Archery Aid cutoff at 12:00 PM
What are the course details for the 100K?
The 100K course begins with a challenging climb up Pritchett Peak, offering a sunrise summit view before descending to the Lake Sonoma Visitor Center. The route continues with a climb to South Lake Trailhead and an out-and-back along the original Lake Sonoma 50 Mile course. The terrain includes madrone groves, lakefront paths, and California carpet singletrack, with relentless hills and remote sections. The course map is available at RaceDayMap ↗.
What are the course details for the 50K?
The 50K course starts with a short paved section before transitioning to rolling singletrack through forested terrain. The route includes climbs and descents through South Lake, Island View, Warm Springs, Wulfow, Liberty Glen, and Bummer aid stations, followed by a bridge crossing and a downhill finish. The course map is available at RaceDayMap ↗.
What are the course details for the Trail Sisters Women's Half Marathon?
The Trail Sisters Women's Half Marathon is a 13.1-mile point-to-point course starting at the Lone Rock Trailhead and finishing at the Lake Sonoma Visitor Center. The route features rolling terrain and lake overlooks, with a community-focused atmosphere. A shuttle will transport runners back to the start, and finish line drop bags will be shuttled from the start. The course map is available at RaceDayMap ↗.
What are the aid station details for the 100K?
The 100K features 13 aid stations, including 8 full service and 5 water-only stations. Water-only stations are located at Pritchett, South Lake, and Wulfow. Full service stations include Woodbridge, Warm Springs, and Liberty Glen, among others. Crew access is available at South Lake (outbound only), Warm Springs, and Liberty Glen, while drop bags can be left at Woodbridge, Warm Springs, Liberty Glen, and Lone Rock. A headlamp is required if leaving Warm Springs after 3:30 PM.
What are the aid station details for the 50K?
The 50K has 6 aid stations, including 4 full service and 2 water-only stations. Water-only stations are located at South Lake and Wulfow. Full service aid stations include Warm Springs and Liberty Glen. Crew access is available only at Liberty Glen, and drop bags can be left at Warm Springs and Liberty Glen.
What are the aid station details for the Trail Sisters Women's Half Marathon?
The Trail Sisters Women's Half Marathon has 3 aid stations: Oak Knoll at mile 3.6, Archery at mile 6.2 (with a cutoff at 12:00 PM), and Bummer at mile 9.7. There is no crew access at Bummer.
What are the race rules?
All distances are cupless, and runners must carry their own bottle, flask, or bladder. Pacers are not allowed for any distance. The event emphasizes self-sufficiency and requires runners to be prepared for long stretches between aid stations, especially on the 100K and 50K courses.
How much does registration cost?
- →100K: $280 early / $300 regular
- →50K: $185 early / $200 regular
- →Trail Sisters Half: $110 early / $115 regular
What is included in registration?
All finishers receive a custom race tote and post-race pizza from Happy Cat Pizza. 100K and 50K finishers also receive a custom bottle of wine (or non-alcoholic option), while half marathon finishers receive a Trail Sisters finisher mug. Live timing is provided by UltraLive ↗, and music is provided by DJ Marco.
What are the refund and cancellation policies?
Registration is non-refundable, non-transferable, and non-deferrable, except for pregnancy deferrals. A 50% refund is available if canceled on or before December 31st (race cost only; processing fee non-refundable). Distance downgrades are permitted on or before April 1st.
What are the practical details for registration?
Registration for the event opens on October 1. Runners are encouraged to register early to secure their spot and take advantage of early bird pricing. The event attracts runners of all levels, from elite ultra runners to community trail runners.
