Annadel State Park Annadel State Park Annadel State Park , a wilderness at your doorstep, is just sixty miles north of San Francisco on the eastern edge of Santa Rosa. Hikers, horsemen, photographers, anglers, and joggers enjoy its 35 miles of trail, and there are nearly 5,000 acres of rolling hills, intermittent streams, meadows, and woodland, unmarred by modern intrusions. The park includes what many biologists consider the best example of northern oak woodlands in existence. See the Area Map. Rainfall averages about 30 inches a year, most of it during the winter and early spring.
Snow is quite rare, and there is little fog.
The park offers many miles of trails for hiking, horseback riding, mountain biking, and trail riding . Lake Ilsanjo offers fishing . There is no camping in the park. It offers some of the most beautiful and bountiful displays of wildflowers from early March to late May . On certain dates, there are docent-led walks which offer visitors interpretive talks of the history and ecology of the park.