Experience the natural beauty of Annadel State Park at the annual Half Marathon, 10K, and 5K races. For over a decade, this non-profit event has raised funds to enhance Trione-Annadel State Park, making it an even more delightful destination for nature enthusiasts. The race returns in 2027, promising runners of all abilities a memorable day filled with scenic trails and camaraderie. Runners can choose from three distances: the Half Marathon offers a challenging yet rewarding 13.1 miles, while the 10K (6.2 miles) and 5K (3.1 miles) provide great options for walkers and first-time participants alike. The course winds through picturesque landscapes, offering stunning views of the park's flora and fauna. Each participant will receive a race medal, an event shirt, and enjoy post-race refreshments. Join us for a day that combines running with community support and environmental stewardship. Celebrate Earth Day (April 24) by participating in our low-waste event, which features cup-free aid stations and refill options. Your contribution helps protect the park we all love—every mile contributes to preserving its beauty and enhancing visitor experiences. A portion of your race registration will be donated to Trione-Annadel State Park and the Sonoma County Parks Foundation, ensuring that future generations can enjoy this natural wonderland. Please note that all registrations are final and non-refundable; however, we encourage participants to consider purchasing race protection insurance for added peace of mind. Mark your calendars for 2027—let's make it another successful year in the tradition of supporting our beloved park!
Races Offered
10K
Apr 17, 2027
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Distance —
10K
terrain
Type —
Running
timer
09:00
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$62.48
5K
Apr 17, 2027
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Distance —
5K
terrain
Type —
Running
timer
09:00
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$56.99
Half Marathon
Apr 17, 2027
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Distance —
21K
terrain
Type —
Running
timer
09:00
sell
$111.98
Weather History
These values represent the 3-year monthly averages for April in Santa Rosa.
thermostatTemperature
7.6° / 19.9°
wb_sunnyFeels like
5.6° / 17.4°
light_mode
Avg sunshine hours
11h 11m
water_drop
Avg rainfall
0.6 mm
ac_unit
Avg snowfall
—
air
Avg wind speed
7.8 km/h (Light breeze)
opacity
Sweat loss rate
Low
terrain
Course conditions
Firm and slightly soft
sunny
Max UV Index
Moderate (5.0)
humidity_mid
Humidity
73.0%
wb_twilight
Sunrise
06:33
nightlight
Sunset
19:47
About Santa Rosa
Learn more about the host city, Santa Rosa.
Santa Rosa is the largest city in Sonoma County, California, and fifth largest in the San Francisco Bay Area. The city is a jumping off point for visiting the wine country of Sonoma County and the Napa Valley, or driving out to the beautiful coastal and parks throughout the Sonoma County.