Trione-Annadel State Park 
6201 Channel Drive Santa Rosa
Sonoma, CA 95409
707-539-3911
http://www.parks.ca.gov/default.asp?page_id=480
State Park: Bike, Birding, Fish, Hike, Picnic, Walk
The park, 60 miles north of San Francisco on the eastern edge of Santa Rosa offers miles of trails for hiking, mountain biking, and trail riding.