Castle Rock State Park (SF Bay Area)

Santa Cruz Mountains from Goat Rock

4.5 miles loop, 1050 feet elevation gain
Difficulty: Moderate, some mild rock scrambling

Access: Paved road to trailhead, Castle Rock State Park entrance fee required

Castle Rock is a popular state park just outside San Jose, California with enjoyable views over the forested Santa Cruz Mountains. This loop through the park utilizes the Saratoga Gap and Ridge Trails and delivers some great views over canyons and ridges of redwoods. While a shorter version of this loop is an extremely popular hike with locals, considering doing this slightly longer loop for more views and to have a brief escape from the crowds that pack this trail on weekends.

Castle Rock is a very short drive from San Jose and the South Bay. Approaching from CA Highway 85, we took the exit for Saratoga Ave and followed Saratoga Ave southwest through the town of Saratoga, where it became CA Highway 9. We followed the windy CA Highway 9 through many twists and turns up to Saratoga Gap and then turned left onto Skyline Blvd (CA Highway 35) at the gap. We followed Skyline Blvd south for 2.5 miles and then turned off on the left into the Castle Rock State Park parking area. This newly constructed entrance for Castle Rock State Park has a large parking lot with well over a hundred spots; still, this is a popular destination and parking can fill on nice weekends. State park entrance fees were payable at a kiosk at the trailhead.

Two trails lead out from the new parking area: we took the one on the right, which leaves from right next to the ranger kiosk and passes a picnic area. This trail- the Waterfall Connector Trail- then descended into the forest and joined with the Saratoga Gap Trail at 0.3 miles. At the junction, we took the right fork, which followed the Saratoga Gap Trail downhill along Kings Creek through some scenic woodlands.

Woods along the Saratoga Gap Trail

We crossed a footbridge over Kings Creek and came to a second trail junction at 0.45 miles. Here, the Ridge Trail ascended off to the right while the Saratoga Gap continued a gradual descent to the left. We stayed on the Saratoga Gap Trail to the left, continuing through the forest.

At 0.6 miles, the trail passed by a viewing platform for Castle Rock Falls. This platform was closed at the time of my second hike but had been open during a previous visit; however, you're not missing much if it's closed. I was very unimpressed by the waterfall during my initial visit: it's simply a trickle down a smooth rock face. This waterfall could be worth seeing after heavy rainfall but otherwise is fine to skip.

The descent ended shortly after passing the waterfall and the Saratoga Gap soon opened up into the chaparral-covered southern slopes of Goat Rock. The trail had many short stretches of ups and downs here and crossed over many small rocky outcrops; while not particularly difficult, some hikers may find that they need to use their hands. For the next mile and a half, the trail was filled with constant views, mainly to the southwest, encompassing the redwood-filled San Lorenzo watershed below us and stretching all the way to the Pacific Ocean. A large swath of these forests were burned in the 2020 CZU August Lightning Complex Fire, which was sparked by an intense thunderstorm in the area and ended up burning the better part of a hundred thousand acres of the San Francisco Peninsula, including the redwoods of beloved Big Basin State Park. 

View over the Santa Cruz Mountains from the Saratoga Gap Trail

The trail passed through a forest in a gulch at 1.1 miles; here, a spur trail to the left descended briefly to visit a small grove of second growth redwoods, the only redwoods growing directly along the trail on this hike.

Second growth redwoods just off the Saratoga Gap Trail

Past the redwoods, we returned to the open slopes with wide views. Looking to the south, I soon realized that the views here extended beyond the local Santa Cruz Mountains: I could see all the way down to Monterey Bay and the Santa Lucia Mountains that form the backbone of the Big Sur region. The many rocky outcrops of Goat Rock rose above the trail. Although the views were good, there were few places to stop and enjoy them: the trail was not terribly wide, there were lots of hikers, and the few outcrops and wide spots in the trail were mostly already occupied by other visitors.

Santa Cruz and Santa Lucia Ranges

Goat Rock

While the forests below in the San Lorenzo watershed were lush and filled with redwoods, the southern slopes of Goat Rock were much drier, sporting oak trees and some deciduous bushes. This meant that there was a nice bit of fall color here during our early December visit, with patches of yellow and red color in the bushes and trees.

Fall on the Saratoga Gap Trail

At 1.4 miles, the Saratoga Gap Trail came to a junction with a connector trail leading over to the Ridge Trail. Almost all of the hikers that we saw here took the right fork and headed up the connector trail for a short loop: doing so trims this to a 3-mile loop hike. However, because almost all visitors do shorten their hike here, it's well worth it to continue onward on the Saratoga Gap Trail and enjoy the scenery on the farther loop, which sees minimal foot traffic.

At 1.5 miles, we rounded a ridge and came to a great view to the northwest along the Santa Cruz Mountains. Here, we could see some mountains that we hadn't been able to see earlier on the Saratoga Gap Trail, including heavily forested Butano Ridge. From this point, the Saratoga Gap Trail continued descending steadily over the next half mile through the chaparral covered slopes. We enjoyed the constant views of the surrounding mountains.

Looking northwest along the Santa Cruz Mountains

Redwood-filled drainage of the San Lorenzo River

At 2 miles, the trail crossed a very steep and rocky part of the mountain slope. Some rock scrambling was necessary here and a cable bolted to the rock provided a handhold for a narrow crossing over a cliff. Acrophobes may have a bit of trouble here but this stretch was really not as bad as it looked or sounds. This short cliff walk also marked the low elevation point of the hike.

Cables on the Saratoga Gap Trail

After completing the cliff walk, we caught some final views before the Saratoga Gap Trail returned to the forest and then made a sharp turn around the ridge at 2.1 miles. The trail passed through a drier forest of madrone and oak here, with occasional lusher patches sporting ferns on the forest floor. While the Saratoga Gap Trail had been fairly quiet, we began hearing constant gunshots here, the sound drifting over from a nearby gun club. At 2.3 miles, we arrived a junction with the Ridge Trail and a trail leading to the Castle Rock Trail Camp; we took the right fork here and began the return leg of the loop on the Ridge Trail.

Ferns growing in the understory on the Saratoga Gap Trail

The Ridge Trail started with a steady ascent through a madrone forest to Russell Point, a viewpoint along the ridge of Castle Rock at 2.5 miles into the hike that had a nice view out over the San Lorenzo watershed, quite similar to the views we had seen along the Saratoga Gap Trail. Leaving Russell Point, we started on an extended ascent along the forested ridge. After passing around the back side of Varian Peak, the Ridge Trail dropped slightly to a saddle at 3.2 miles where it intersected with the connector trail that we had passed earlier. We had enjoyed complete solitude while hiking the far end of the loop, but once we passed the junction with the connector trail there was once again a good bit of traffic on the Ridge Trail.

The Ridge Trail continued uphill through the woods. At 3.3 miles, we made a short detour to a nice viewpoint on the right side of the trail where we could see out to the Santa Lucia Mountains again. At 3.7 miles, we took the right fork at a junction with the trail leading to the interpretive center. The Ridge Trail swung to the south and ascended just a bit more to reach the high point of the hike at Goat Rock at 3.9 miles. The rock itself was off to the right of the trail and required some scrambling to reach the top; we decided to skip the scramble and instead visit some of the other nearby viewpoints.

Views from the Ridge Trail

Leaving Goat Rock, the trail dropped a beautiful staircase where distant ridges were visible through the gaps in foliage of the colorful deciduous trees above. 

Forested trail at Goat Rock

At the bottom of the staircase, the trail came to an open rocky outcrop with beautiful views. Goat Rock rose to the northwest; this massive sandstone outcrop has a remarkable honeycomb structure known as tafoni, which occurs in various places along the California coast. The rock is very popular with rock climbers: we saw a couple of climbers on the rock during our visit. Although we were hiking in Castle Rock State Park, many of the best views and most impressive rock outcrops in the park were at Goat Rock: Castle Rock, a sandstone outcrop further to the east, is in a more subdued setting. The overlook also provided some lovely final views of the Santa Cruz Mountains.

Goat Rock

Sunset over the Santa Cruz Mountains from Goat Rock

As the sun set, we made our way back down the final stretch of the Ridge Trail, which descended steadily through some rocky stretches to return to the junction with the Saratoga Gap Trail at 4.1 miles. From the junction, we followed the Saratoga Gap and then the Waterfall Connector Trail back uphill to the parking lot.

This is a nice hike that is a very short drive from the San Jose area, which could be either a positive or negative attribute. The views are enjoyable but the trail is often crowded; hike the whole loop to find some solitude as the loop's far end. Visitors with limited time in the Bay would be better served heading to big name summits like Diablo or Mt. Tam but this is a good option for local hikers looking for a scenic half-day jaunt.