Lake Sonoma 100K, 50K, TS Half Marathon

Event Overview

Join us in Healdsburg, California, on April 11th 2026 for the TERREX Lake Sonoma 100K, 50K, and Trail Sisters Half Marathon! We are excited to have adidas TERREX back as our presenting partner!

We are stoked to team up with Mountain Outpost to bring you full livestream coverage, athlete panels, interviews, and commentary from special guests!

Lake Sonoma 100K

• Course Challenge: The 100K course will start with a climb up Pritchett Peak with a water-only stop at the top.
• Trail Details: Once you reach the summit, you’ll head back down toward the Lake Sonoma Visitors Center and then up to the hill to South Lake Trailhead.
• Experience: You’ll embark on an out and back of the original old school LS course and then back down the hill to the finish.
• Unique Features: It’s the same great Lake Sonoma Relentless experience, only this time with a big climb to kick it all off!

Lake Sonoma 50K

• Start Location: The 50k start is located in the green space next to the Lake Sonoma Visitor Center.
• Course Path: After a short road section to get the field spread out, the course then continues onto beautiful rolling single track trails.
• Scenic Route: You will continue past South Lake, Island View, Warm Springs Creek, Wulfow, Liberty Glen, and the Bummer aid stations.
• Final Challenge: Remember to save some juice for the last few miles, as you have a screaming downhill towards the finish. The race starts at 7:30 am.

Trail Sisters Women's Half Marathon

• Women’s Event: The Trail Sisters (TS) Half Marathon is a women’s only event created to foster encouragement and camaraderie.
• Course Type: This out and back course starts with steep trail ascent to South Lake Trailhead, providing a speedy descent to the finish.
• Hilly Terrain: Expect relentless rolling hills that will challenge your mind and body.
• Supportive Community: You will share the journey with a community of supportive Trail Sisters to help you through! You will have 4 and half hours to complete the half marathon course.

Come Celebrate!

Lake Sonoma isn’t just a race event, it’s a celebration. We always complete the weekend with a Celebration and Thank You event at Coyote Sonoma in Healdsburg, CA. Everyone involved with the event is invited to enjoy wine, charcuterie, and share stories from the weekend.

See You on the Start Line!

Gina & Justin
LS Race Directors

For more information, visit Lake Sonoma Official Race Page.