91. Las Trampas Regional Wilderness

Length:	Rocky Ridge, 6.3-mile loop; Las Trampas Ridge, 9.2 miles round trip
Hiking time:	4 hours for Rocky Ridge, 6 hours for Las Trampas Ridge
High point:	2,000 feet
Total elevation gain:	1,150 feet for Rocky Ridge, 2,100 feet for Las Trampas Ridge
Difficulty:	moderate
Season:	year-round
Water:	bring your own
Maps:	USGS 7.5' Las Trampas Ridge, park brochure
Information:	East Bay Regional Park District

The steep hills of Las Trampas Regional Wilderness host a variety of plant communitiesflower-dotted meadows, vast thickets of multi- scented chaparral, lush streamside habitat, oak-studded hillsidesand they allow extensive vistas of the Bay Area.

To reach the trailhead, first get to the intersection of Crow Canyon Road and Bollinger Canyon Road by traveling 7.3 miles on Crow Canyon Road from I-580 in Castro Valley, or by traveling 1.6 miles on Crow Canyon Road from I-680 in San Ramon. Then take Bollinger Canyon Road 4.4 miles northwest to its end. Be sure to grab the park brochure; it'll help you navigate the trails.

The 6.3-mile loop on and around Rocky Ridge begins with a long climb on the paved Rocky Ridge Trail. Groves of live oak and California laurel dot the open hillside, interrupting extensive meadows. At 0.4 mile the Cuesta Trail comes in on the left. You'll use this path to complete the loop journey, but for now continue up to a road gate at 0.7 mile and turn left onto the Upper Trail.

You now travel just below Rocky Ridge. A look eastward shows Bollinger Canyon below, with chaparral-cloaked Las Trampas Ridge just above and Mount Diablo looming in the distance beyond. As you continue, look for fossil clam shells embedded in the sandstone rock.

Turn right onto the Sycamore Trail at 1.5 miles and enjoy views of the East Bay hills, San Francisco Bay, the entire peninsula, including San Francisco, and the Santa Cruz Mountains and Coast Range stretching to the south.

Reach a shoulder at 1.7 miles and drop past chaparral, grassy hillsides, and coast live oak groves to a seasonal creek at 2.7 miles, which is amply shaded by California laurel, canyon live oak, and a few California sycamores. Stay on the main trail at a fork just beyond the creek, then turn left onto Devils Hole Trail at 2.8 miles.

Climb steeply, regain the spine of Rocky Ridge, and turn left onto the Upper Trail at 4.1 miles. Take a right onto the Cuesta Trail at 4.5 miles, cross a trail, and hike downhill to connect with the paved Rocky Ridge Trail at 5.9 miles. Go right for 0.4 mile back to the trailhead.

The 9.2-mile hike on and around Las Trampas Ridge begins with the Creek Trail on the west side of Bollinger Creek next to a huge coast live oak. Cross the creek at 0.6 mile underneath some California laurel trees, then bear left 25 yards farther onto the Valley Trail. Go right onto the Grasslands Trail 0.3 mile farther at a saddle and begin climbing.

At 1.7 miles bear right onto the Las Trampas Ridge Trail. It levels in a chaparral thicket, then meets a three-way signed trail junction, where you go left onto the Nordstrom Trail. Hike 0.3 mile past madrone trees, then bear left onto the Ohlone Trail. After 150 yards the way becomes a gulch that climbs straight toward Eagle Peak. Scamper up its knoll for excellent views of Mount Diablo, the San Ramon Valley, San Pablo Bay, and Rocky Ridge.

Continue down the Ohlone Trail to a saddle at 4.3 miles, where you bear right onto the Madrone Trail. Drop past oak woodlands, arc sharply right, then gradually climb to the Virgil Williams Trail at 5.2 miles, where you bear right. Admire Mount Diablo on the left, then go right at 6.2 miles onto the Springs Trail and climb to the crest. Head left here at 7 miles onto the Summit Trail.

Go right at 7.5 miles on the Vista Trail and stroll past chamise, salvia and artemisia sage, and ceanothus. Turn left onto the Trapline Trail at 8 miles next to Oak Circle, then go left again 0.1 mile farther. At 8.6 miles bear left onto the Mahogany Trail. Hug a rapidly descending seasonal stream, then, at 8.8 miles, go left onto the Chamise Trail. Reach Bollinger Canyon Road 0.2 mile farther and turn right for the brief walk to the trailhead.