Mount Saint Helena, in California’s Mayacamas range, rises across Napa, Sonoma, and Lake counties from uplifted volcanic rocks tied to the Clear Lake Volcanic Field. One of the few San Francisco Bay Area peaks that can receive winter snow, it also marks the source of the Napa River on its southeast slope. Its five peaks include North Peak in Sonoma County and Napa County’s highest point just east of the main summit. The mountain’s older volcanic activity is linked to the creation of California’s Petrified Forest. Known earlier as Kanamota and Mount Mayacamas, it later became associated with Robert Louis Stevenson and other literary figures.