Sunol Regional Wilderness

Sunol Regional Wilderness

8 miles loop, 2150 feet elevation gain
Difficulty: Moderate
Access: $5 per car entrance fee for Sunol Regional Wilderness

Sunol Regional Wilderness is a brilliant tract of East Bay countryside less than an hour from San Francisco or San Jose. In the park's rolling, oak-studded hills and verdant canyons, it's easy to forget that Silicon Valley and the bustle of SoMa aren't far off; with few exceptions, the views along this hike are confined to the green countryside of Sunol, with little hint of the metropolis just miles away. There are almost continuous views on this hike, which visits the summit of cliff-lined Flag Hill before following the open ridgeline of Vista Grande and visiting the open slopes of Cerro Este. The hike ends by visiting the pretty gorge at Little Yosemite before returning to the visitor center at the base of Flag Hill. While this certainly isn't a must-hike, visiting the many ridges of the Sunol Wilderness can make for a fun day with lots of views away from the crowds of Mount Tam or Mission Peak. The park provides a good map that makes finding your way on this loop quite easy.

I hiked this trail on a warm, beautiful January day with totally clear blue skies. I left San Francisco with my good friend from high school and college in the morning, with far-reaching, smog-less views as we crossed the Bay Bridge. Across the bay, we took I-580 east past Castro Valley and across the mountains to the junction with I-680, which we followed south to exit 21A for Sunol and Calaveras Road. We followed Calaveras Road south for a few miles until we reached Geary Road, which we turned left onto and followed to the park. We paid the $5 entrance fee and met up at the park with a former roommate who now attended Stanford, who had come with one of his friends.

The four of us set out on the hike by crossing the bone-dry Alameda Creek on a bridge next to the Visitor Center. We then headed left, following the Flag Hill Trail a quarter mile past the junction for the Shady Glen Trail. The trail then began a fairly steep and aggressive ascent up Flag Hill. Early on, we hiked past beautiful, gnarled old oaks growing amidst the verdant meadows. Flag Hill itself soon came into sight, its cliff-hemmed summit resembling ramparts of some old castle.

Sunol Regional Wilderness

Flag Hill

As we headed uphill, we passed occasional fences that ran across the hillside. We assumed that these were for the many cows in the park, some of which we could already see in the distance.

Further uphill, the trees faded away and the landscape was dominated by grass and shrubs that had assumed their winter green on hills that would turn to yellow and brown by summer. The views improved dramatically as well: behind us, we could see the parking lot and a growing portion of the rolling hills, while to the east we could see the rounded summits of Cerro Este.

Ascending Flag Hill

After a strong push and a thousand feet of ascent in a mile from the bottom of the valley, we reached the top of Flag Hill. The trail looped to the east around the hill's dramatic ramparts before reaching the small mountain's flat top. At the summit, views to the north opened up: in the far distance, we could see the two peaks of Mount Diablo and the twin summits of the Maguire Peaks. To the west, we could see communications towers rising from the summit of Mission Peak.

We enjoyed the view at the top for a while. Even though this hike visited many ridges, Flag Hill was the only actual summit on the route, making its 360-degree view especially worthwhile.

From the summit, we took the Flag Hill Road north and east down towards the saddle between the hill and Vista Grande. This wide trail made a curving switchback down the east side of Flag Hill. On our way down to the saddle, we passed a picturesque pond set in a small basin, backed by the Maguire Peaks.

Maguire Peaks and a pond on the slopes of Flag Hill

We reached the saddle about three-quarters of a mile from the summit of Flag Hill and 2 miles from the start of the hike. The saddle marked a four-way junction between the High Valley Road, the Flag Hill Road, and the Vista Grande Road. We headed directly across the intersection from the Flag Hill Road onto the Vista Grande Road. At the junction, there were a number of cows grazing next to the trail. We paused at a distance of a least fifty yards to photograph them, but this was apparently already too close for comfort for one of the cows, which glanced up at us and then began a steady trot towards us. We backed off; the cow went back to eating.

Cows

The Vista Grande Road quickly made its way up from the saddle to the ridgeline. The vista was indeed grande: this was perhaps the most scenic portion of trail on the hike. Early on the ascent along the ridgeline, there were great views to the north of Mount Diablo and the Maguire Peaks; further along the ascent, we looked behind our shoulder to pretty views of the ridgeline we had hiked up stretching towards Mission Peak. Cerro Este appeared as a hill of green velvet before us and below the ridge to the south we saw High Valley Camp and the Calaveras Reservoir.

On Vista Grande

High Valley Camp from Vista Grande

Vista Grande Trail

About three miles into the hike, we paused at a bench along the Vista Grande Trail to lunch and enjoy the sweeping the view of most of the Sunol Wilderness. "Wilderness" is a bit of a misnomer for this park: although Sunol is certainly less developed than Silicon Valley or the suburbia of East Bay, there are still structures built throughout the park and benches along road-width trails.

Past the bench, came to a junction with the Eagle View Trail. We took the right fork, which brought us onto the narrower, single-track Eagle View Trail heading south and east. This portion of trail was quite spectacular: the trail was set into a steep grassy slope with a drop-off to the right of the trail. As we hiked forward, we had continuously good views of Cerro Este. "Eagle View" was certainly appropriately named.

The Eagle View Trail dropped into a canyon as it approached the flanks of Cerro Este. Briefly leaving the grassy meadows, the trail entered a small gully lined with oaks and crossed the stream flowing through the canyon before climbing back out onto the grassy meadows along the west side of Cerro Este. At the junction with the Eagle View Road, we stayed on the left fork for the Eagle View Trail, which passed a number of pretty rock outcrops and continued along open slopes until reaching the Cave Rocks Road at about 4 miles from the trailhead.

On the Eagle View Trail

We took the right fork when the Eagle View Trail merged onto the Cave Rocks Road. The Cave Rocks Road followed the contours of Cerro Este, taking us away from the more exposed slopes with wider views. Along the way, we passed by another pond, some cows, and many solitary oak trees. After passing the pond, the trail started ascending more steadily once more. We noticed some odd terraced structures on the slopes of Cerro Este uphill of the trail and were unfortunately unable to learn where they originated.

Pond on Cave Rocks Road

Three-fifths of a mile after merging onto the Cave Rocks Road, the trail gained the ridgeline and joined the Cerro Este Trail. At about 1700 feet above sea level, this junction, although not a summit, was the highest point of the hike. We could see green hills stretching out in all directions, including some more heavily forested mountains to the east that we had not seen previously that day. Far off to the west, we could see the mountains running along the peninsula as well as San Francisco Bay itself; farther to the north and very far in the distance, we could make out the skyline of San Francisco itself, with the Transamerica Pyramid, the Coit Tower, and the Bay Bridge all identifiable.

San Francisco from Cerro Este Road

The ridgeline was quite windy, so after stopping briefly for photos we began following the Cerro Este Road downhill. This trail continued along the ridge, dropping gradually as it passed a beautiful lone oak tree and then a number of small ponds, each of which hosted a number of thirsty cows. Although the views gradually diminished as we headed downhill, the scenery was consistently good as the trail remained more or less in the open and the path was constantly surrounded by green grass and picturesque trees.

Sunol countryside

Cows along the Cerro Este Road

We followed the trail downhill past the junctions for the McCorkle Trail and the Canyon View Trail. The further we hiked, the less far we could see: the Calaveras Reservoir was initially visible directly before us but gradually disappeared behind the hills as we dropped towards the bottom of the canyon along Alameda Creek. At one point, a large, exposed outcrop was visible just uphill of the trail, marking the most interesting rock feature on the hike since the cliffs on Flag Hill. After following the Cerro Este Road for almost two miles since joining that trail after the junction with Cave Rocks Road, we came to the Camp Ohlone Road at the bottom of the canyon; the total distance covered at this point was about 6.5 miles. We continued past the road, going downhill just a slight bit more to reach the creek inside Little Yosemite. Even with the qualifier "little," the name is a bit of a misnomer: the largest features in the canyon are rocks perhaps only tens of feet in height. Still, the rock eroded rock walls of the canyon were pretty and allowed for us to scramble downstream just a bit to a small waterfall and a set of shallow pools.

Little Yosemite

After a short stop at Little Yosemite, we headed back uphill along the Cerro Este Road about a fifth of a mile to the junction with the Canyon View Trail. We took the the Canyon View Trail west (to the left). The trail climbed a bit and followed the side of the hills fairly high above the canyon of Alameda Creek. After a short while of following the canyon, the trail swerved to the right and reentered the landscape of rolling hills. The cliffs rimming Flag Hill, our destination earlier in the day, appeared before us, indicating that our loop was approaching its end. After passing the McCorkle Trail once more, the trail made a final descent back to the side of Alameda Creek. We followed the trail along the creek past the Indian Joe Nature Trail until we reached the bridge near the visitor center where we had started the hike in the morning.

View into the canyon

After finishing our hike, we hurried back to San Francisco to catch a key ACC basketball game airing that afternoon.

Hiking in the Sunol is a thoroughly enjoyable experience. Although the scenery is rarely jaw-dropping, there are more or less continuous views along the trail and the countryside that the loop traverses is very pleasant. Bay Area hikers should certainly not miss out on hiking in the Sunol Wilderness; however, while visitors would likely find this hike enjoyable as well, the scenery here is certainly not exemplary in Northern California.