SUNDAY DRIVE
Sunol’s Flag Hill
What you’ll see: Flag Hill rises 800 feet above a gorgeous valley and miles of wilderness foothills. On top, you get an eye-level view of raptors, which use the rising thermals for lift to glide, circle and hunt the region’s high numbers of ground squirrels. You also get tremendous 360-degree views across the Ohlone Wilderness (to the east) and watershed lands, Calaveras Reservoir (to the south) and San Antonio Reservoir (to the north).
Location: Near Sunol off Interstate 680 in Contra Costa County.
The hike: From the parking area near the Old Green Barn Visitor Center, cross the footbridge over Alameda Creek and connect to Hayfield Road. This becomes a rhythmic climb, wide so you can walk side by side as you climb for 0.8 of a mile to the cutoff for High Valley Camp (for now, camping is temporarily closed at this site). Turn left on High Valley Road and continue 0.4 of a mile to Flag Hill Road. Turn left and climb the final 0.8 of a mile to the summit of 1,360-foot Flag Hill. Synopsis: 4.2-mile round trip, 800-foot climb on way up.
Option: Some take the Flag Hill Trail, half the length, twice as steep.
Raptors: Red-tailed hawks, prairie falcons and turkey vultures are the most common, but peregrine falcons and golden eagles are occasionally seen. At dusk, keep an eye out for great horned owls. The crevices in the nearly vertical rock outcrops provide nesting areas for hawks and falcons.
Look closely: The rock outcrops on top of Flag Hill have embedded fossilized shells; the mountain used to be covered by the ocean.
Where’s everybody going? On weekends, you’ll see numerous cars parked at the end of the road at the eastern end of the valley. This is the trailhead for Little Yosemite, an easy walk to a set of small pool-and-drop waterfalls in a small, rocky gorge. A detailed story and video is archived from Feb. 4, 2016, at www.sfchronicle.com.
Trail rules: Dogs, mountain bikes allowed.
Cost: $5 per vehicle, $2 for dogs.
Map/brochure: Free at visitor center; PDF at www.ebparks.org.
Contact: Sunol Regional Wilderness, (510) 544-3249 or (888) 327-2757, option 3, Ext. 4559; East Bay Regional Park District, www.ebparks.org.
HOW TO GET THERE
GPS: Use 1895 Geary Road, Sunol.
How to get there: From San Francisco, take the Bay Bridge east for 6.4 miles (stay far right) to the split and Interstate 580. Bear right on I-580 east and drive 26 miles to I-680 south. Take the exit to I-680 south and go 8.3 miles to the exit for Calaveras Road/Highway 84. Take that exit, merge onto Highway 84 (a two-laner) and continue a short distance to Calaveras Road. Turn left and drive (under I-680) 4.3 miles (watch for bikes) to Geary Road (signed for the regional wilderness park). Turn left on Geary and drive 2.3 miles (becomes narrow, no stopping, watch for bikes) to the park entrance and kiosk. Continue to parking on the left for the Old Green Barn Visitor Center.
Distances: 6 miles from Sunol, 16 miles from Dublin, 25 miles from Santa Clara (measured from Levi’s Stadium), 33 miles from Walnut Creek, 42 miles from San Mateo, 49 miles from downtown San Francisco, 52 miles from Half Moon Bay, 60 miles from San Rafael.