Annadel Half Marathon & 5K

Sunday, April 7, 2024 • Santa Rosa, CA • Course Map

With more than 30 miles of trails that wind through its nearly 5,000 acres of wooded forests, hills, open meadows and occasional creeks and streams, Annadel State Park offers what organizers say is a “gnarly” half marathon trail run with plenty of hills and uneven terrain, as well as gorgeous views of the wildflowers that are just beginning to bloom in the spring.

Officially a fundraiser for the park, the Annadel Half Marathon marks its 9th annual this year, and welcomes a few hundred runners each year.

Runners follow mostly single-track trails through forested hills and meadows for most of the course, which follows an out-and-back route that starts and finishes at the swimming lagoon area of Spring Lake Regional Park, which lies adjacent to Annadel along its western edge.

From there, runners head out and make a clockwise loop through the park’s hills, starting out on the Spring Creek Trail and then heading into the park just after the first mile marker.

In addition to the 13.1-mile race and 10K, organizers also plan to host the 5K in conjunction with the Annadel Half Marathon. Like the half marathon, the 5K also is a fundraiser that will benefit the Sonoma County Regional Parks Foundation to build new trails in the regional parks.

Race Weather & Climate

Located in Northern California’s Sonoma County, just over 55 miles northwest of downtown San Francisco, Santa Rosa typically sees mild to moderately warm weather in April, with temperatures ranging from the low 50s to the low 80s.

On race day (April 7), the average low is 53ºF and the average high is 80ºF.

Past Results

Course Map

See the race route map for the Annadel Half Marathon here.

Starting Time

8:00 AM


  • $90 for the half marathon
  • $70 for the 10K
  • $60 for the 5K


To reserve your spot in the spring 2024 running of Santa Rosa’s Annadel Half Marathon or Kathy’s Race 5K, register online at

Official Race Website


Ever run in the Annadel Half Marathon? Share your impressions here, or post your review in the Comments below.

See more races in: April, California

1 comment… add one
  • Jennifer West October 19, 2015, 6:46 pm


    When does registration open for the 2016 Annadel Half?

    Thank you!


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