Annadel Half Marathon

Annadel Half Marathon/10K/5K

The Annadel Half Marathon, 10K, and 5K

The Annadel Half Marathon is a non-profit fundraising event that, over the past 15 years, has raised significant funds to help make Trione-Annadel State Park a more beautiful place for everyone to enjoy. Thanks to the incredible support of our sponsors, participants, and volunteers, this race has become one of Sonoma County’s premier running traditions — and we’re excited to return in 2026!

The Half Marathon, 10K, and 5K are among the biggest running events in Sonoma County, drawing runners of all levels to the scenic trails of Annadel State Park.

• Half Marathon: 4-hour cut-off time

• 10K & 5K: Great options for walkers and first-time participants

Each participant receives a race medal, a event shirt, and post-race beverages and snacks.

Join us for a day of running, community, and supporting the park we all love!

Protect the Place You Race

In honor of Earth Day (April 22), we’re proud to host a low-waste event with cup-free aid stations, refill options, and a focus on park stewardship — because every mile should leave Annadel better than we found it.

A portion of event proceeds is donated to Trione-Annadel State Park and the Sonoma County Parks Foundation.

Please note that all race registrations are final and non-refundable. We encourage participants to consider purchasing race protection insurance during registration for added peace of mind.