Rim Rock 50 Mile Trail Challenge

The Rim Rock 50 Mile Trail Challenge is a bold new addition to the California ultra-running circuit, held at Skyline Wilderness Park in Napa Valley. Scheduled for Saturday, May 16, 2026, this inaugural event is produced by the Trail Squirrel Adventures team. The course offers a rare opportunity to traverse the newly opened Suscol Headwaters Trail System, featuring a landscape of oak forests, grasslands, and panoramic views stretching toward the San Francisco Bay.

The event is designed as a high-endurance test with a strict 13-hour total course cutoff. Runners can choose between a solo endeavor or a two-person relay team.

The course is approximately 52 miles total, utilizing the technical and rugged trail networks of Skyline Wilderness Park and the Napa Open Space Preserve.

• - Elevation and Exposure: The route is evenly split between shaded oak woodlands and fully exposed ridgelines. Participants should be prepared for significant heat in the afternoon.
• - Soscol Headwaters: This section is a 709-acre preserve that connects to the Bay Area Ridge Trail, providing unspoiled backcountry views but no permanent water or restrooms.
• - Cupless Initiative: This is a 100% cupless race. Runners must carry their own hydration packs or reusable silicone cups for refills at aid stations.

The event gate opens at 5:30 AM. This gate is located 1/8 mile before the main park entrance; arriving at the main gate before 7:00 AM will cause delays and require an additional $6 fee.

• - Registration Swag: Solo and relay runners receive a dry-wick T-shirt and a Rimrock Trail Challenge trucker hat upon finishing. Solo winners receive Victory Sportdesign bags.
• - Post-Race Celebration: A full meal featuring burrito wraps, salads, and adult beverages is included for runners. Extra meal tickets for crew members can be purchased during registration.
• - Crew and Pacers: Crew access is limited to the Start/Finish area and the Lake Marie Aid Station. Pacers are only allowed for solo runners during their second 25-mile loop.
• - Camping: Tent and RV sites are available at Skyline Wilderness Park for the weekend (May 15–17), though these must be reserved separately through the park's system.