Annadel Half Marathon

Annadel Half Marathon/10K/5K

The Annadel Half Marathon is a non-profit fundraising event that, over the past 14 years, has raised significant funds to help make the park a more beautiful place for everyone to enjoy. Thanks to the incredible support of our sponsors, participants, and volunteers, this 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

Policies: Sorry, no refunds or transfers

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 running low-waste aid stations, cup less refills, and park stewardship—because every mile should leave Annadel better than we found it. A portion of proceeds is donated to Trione-Annadel State Park and the Sonoma County Parks Foundation.