This race is very popular and sold out. From the official website: “Napa-to-Sonoma is the flagship event in the Wine Country Half Marathon Series. This popular race features a fast and scenic course starting at Cuvaison Carneros Winery and finishing in historic Sonoma Plaza in front of City Hall. The world-renowned Napa and Sonoma Valleys serve as the host of this event, offering the finest in wine country ambience and hospitality.”