Annadel Half Marathon

Santa Rosa, United States • 18 Apr 2026

Event overview

The Annadel Half Marathon is a non-profit fundraising event held at Spring Lake Regional Park, 5585 Newanga Avenue, Santa Rosa, California. The event includes a half marathon, a 10K, and a 5K, and has raised funds to support Trione-Annadel State Park and the Sonoma County Parks Foundation over the past 14 years. The races use the trails around Annadel State Park and include participant amenities such as a race medal, an event shirt, and post-race beverages and snacks.

Race details

  • Half Marathon
  • 10K
  • 5K

The half marathon has a 4-hour cut-off time. The event is organized as a low-waste effort in honor of Earth Day, with cup-free aid stations and refill options and an emphasis on park stewardship. A portion of event proceeds is donated to Trione-Annadel State Park and the Sonoma County Parks Foundation. Registration uses tiered pricing: the listed half marathon fees range from $108.98 to $130.38; the 10K from $60.83 to $76.88; and the 5K from $55.49 to $66.18. The event policy states that refunds are not available. Visit the organization's website for the most recent information.

Race information

21 km
Half Marathon
10 km
10k
5 km
Visit the organization's website for the most recent information.
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