Sonoma State Historic Park   About Your Visit Sonoma State Historic Park is open to the public almost every day of the year. Park staff members are on duty in the Mission and at the Vallejo Home; historical photographs and displays can be seen in the park headquarters building near the Toscano Hotel on the north side of the plaza. A large parking lot has been provided behind the Toscano Hotel and Sonoma Barracks. Petaluma Adobe State Historic Park, which tells still another facet of the Vallejo story, is a twenty minute drive from Sonoma. The huge old adobe ranch building, the largest private hacienda in California between 1834 and 1846, was the center of activity on one of the most prosperous private estates established during the Mexican period. Advance notice of any group visit is appreciated. Appointments for special school-tour educational service (and waiving of fees) are stipulated in joint policy with State Superintendent of Public Instruction; to qualify a class, kindergarten through 12th grade and accompanying adults, the teacher must initiate and have received a confirmed School Reservation Request Form fifteen days prior to class visit. Apply P.O. Box 167, Sonoma, CA 95476 or call (707) 996-1744.