ABOUT TRIONE-ANNADEL STATE PARK
Trione-Annadel State Park is situated at the northern edge of Sonoma Valley and is adjacent to Spring Lake Regional Park in the City of Santa Rosa. Within its 5,200 acres and 40+ miles of hiking, biking and equestrian trails, it offers many recreational and wildlife viewing activities.
Trione-Annadel State Park's interconnected trail system includes an 8.5 mile section of the Bay Area Ridge Trail. The park’s trails are a popular destination for runners, hikers, mountain bikers and equestrians. The variety of single track and wide service roads wind through open grassy hillsides, wooded forests, and oak woodlands. Wildflowers are abundant in Spring and early Summer, especially around Lake Ilsanjo. Waterfalls and rushing creeks pour from the park hillsides during rainy winter months to the delight of intrepid visitors.
The 26-acre Lake Ilsanjo provides fishing opportunities for those willing to hike in their fishing gear. Bluegill and Black Bass—some weighing 9 pounds—have been caught here. The upper Ledson Marsh, which dries up in the fall, is home to 130 different bird species during the year.
Map of Trione-Annadel State Park
These lands were occupied by the Wappo and Pomo people in prehistoric times, who would have primarily inhabited the riparian zones and the marsh perimeter. TASP includes what some biologists consider the best example of undisturbed northern oak woodlands in existence. Visitors can enjoy the park’s diverse wildlife and scenery any time of the year.
The rock formations of TASP have played a central role in its history: its volcanic origins, the Native American use of obsidian, the early 1900s quarrying of basalt cobblestones, and modern hikers’ appreciation of its volcanic outcrops.