Is the Napa to Sonoma Wine Country Half Marathon course certified? Twain June 13, 2019 17:46 Updated The half marathon and 5K courses are certified by USATF. Related articles How do I get from the finish line back to my car? How early should I arrive on race day? How do I get to the start line? Can I get dropped off at the start line? What are the age groups for awards?