Trione-Annadel State Park


What? : Large nature park at the hills east of Santa Rosa, it provide many hiking options. The park hills are covered with oak trees forest spotted by grasslands meadows.


Where? : The park is located east of Santa Rosa and south of Highway 12

Google Map Link


When? : Year round but best wildflowers blooming are between April and May


Due note 1: The large state park is adjacent to Spring Lake Regional Park (nature park with large lake).


Due note 2: Dogs are not allowed on trails.


Due note 3: The park is popular and at weekend it can be crowded and with many mountain bikers but because the long trails you can always find the way to walk without many people.


My thoughts: We spend here a nice winter day and hike only at the west section of the park and enjoy it very much.


The visit:

The proximity to Santa Rosa makes this park popular with hikers, mountain bikers, and equestrians. Some portions of the park burned during the fires of 2017; you will walk through the burned sections, but this does not affect the visit.


We only visit the west section of this large park and at the east side there are much longer hike opportunities, marshlands and large meadows.


The hike (7.5 miles option):

We did not park our car at the main park entrance but rather at Spring Lake Regional Park Shady Oaks parking lot.

Our hike covered a lot of different landscapes from artificial large lake of Spring Lake to the nice Spring creek, large Ilsanjo Lake and the oaks covered hills on our way back.

We started our hike by going to the north dam section and around the large lake.

We keep walking to the west dam, behind the large water tanks and over the south dam.

From here we walk on the wide gravel Canyon Trail along the Spring creek.

At the trail junction where Canyon Trail turn to the right, we keep going on Spring Trail in the main canyon.

After 1.2 mails you will reach Ilsanjo Lake dam section. You can hike around the lake, but we did not have the time to do this.

From the lake dam we went north turning into Rough Go Trail, after 0.5 mile keep going on Rough Go Trail for another 0.6 mile and turn right into Cobblestone Trail. After 0.7 miles you will pass through the old quarry.

Just before the last hike section you will reach an open flat section in the forest where you can see on the other side on your left a road. We went to this road and took the trail that is going down and circling the hill, this trail will lead you directly to the parking lot where we left our cars and started our hike.