California · 10K · 5K · Half Marathon
Annadel Half Marathon
Annadel Half Marathon is a 10K, 5K and half marathon event held in Santa Rosa, California. Its next confirmed date is Saturday, April 17, 2027. About 300 runners take part across all distances.
- Race day
- April 17, 2027
- Location
- Santa Rosa, CA
- Field size
- ~300 runners
Race details
- Date
- Saturday, April 17, 2027
- Location
- Santa Rosa, California
- Distances
- 10K, 5K, Half Marathon
- Field size
- About 300 runners
- Course
- Very hilly/technical trail half marathon; organizer states over 1,500 ft elevation gain over rocky, rooted terrain
- Registration
- raceroster.com
Registration, course & weather
- Registration status
- Open
- Entry fee
- Listed fee for the longest distance, $112 (from annadelhalfmarathon.com, checked September 25, 2026)
- Start time
- 9:00 AM PDT
- Course profile — 5K
- Out-and-back course; Mostly trail, some road
- Course profile — Half Marathon
- Loop course; Trail surface; 1500 ft gain, 1500 ft loss (official course data)
About the Annadel Half Marathon
The Annadel Half Marathon is a nonprofit fundraising trail race through Trione-Annadel State Park near Santa Rosa, CA. The technical, rocky half marathon course climbs over 1,500 feet through oak woodlands and meadows, while the 10K and 5K offer shorter, more approachable options starting from Spring Lake Regional Park. Proceeds support trail improvements in the park.
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Guides from the RaceRove blog
- 8 min read How to Choose the Best Half Marathon for a PR, Racecation or 50-State Challenge The best half marathon depends on what you want from it. How to choose a course for a personal record, a race worth travelling for, or an efficient stop on a 50-state challenge.
- 7 min read How to Find a 5K, 10K, Half Marathon or Marathon Near You A practical way to find running races near you: pick a distance, decide how far you'll travel, read the listing properly and confirm the details before you register.
- 9 min read How to Run a Race in All 50 States How to plan a 50-state running challenge: set your own rules, group states into trips, build a calendar around the seasons, budget for it and keep track of every finish.
- Blog All guides Planning advice for finding, choosing and travelling to races.
Annadel Half Marathon: common questions
- When is the Annadel Half Marathon?
- The next confirmed date is Saturday, April 17, 2027.
- Where is the Annadel Half Marathon held?
- In Santa Rosa, California.
- What distances does the Annadel Half Marathon offer?
- 10K, 5K and Half Marathon.
- How many people run the Annadel Half Marathon?
- About 300 runners across all of its distances. That figure is an estimate of the field size, not an entry cap.
- How do I register for the Annadel Half Marathon?
- Registration is handled by the organiser at raceroster.com. Entry fees, caps and deadlines are set there.
- Is registration open for the Annadel Half Marathon?
- Yes — registration is open. Listed fee for the longest distance, $112 (from annadelhalfmarathon.com, checked September 25, 2026).
- What time does the Annadel Half Marathon start?
- 9:00 AM PDT.
Plan this race in RaceRove
Save it to your plan, compare it with other races, check typical race-day weather and track your 50-state progress in the interactive app.