Calero Bald Peaks

El Toro and the Diablo Range from the Bald Peaks Trail

10 miles loop, 2000 feet elevation gain
Difficulty: Moderate
Access: Paved road to trailhead, no entrance fee required

The Bald Peaks Loop in Calero County Park south of San Jose, California is an enjoyable though ordinary hike through grassy hills with views of the Santa Cruz Mountains and Santa Clara Valley. Calero County Park centers on water recreation on Calero Reservoir, which supplies water to Santa Clara County, but this enjoyable hike follows the ridge behind the reservoir for a nice day-long outing. This hike starts from the McKean Road entrance to the park and follows the Pena, Vallecito, and Canada del Oro Trails to the top of the ridge, then travels along a scenic stretch of the Bald Peaks Trail before returning to the trailhead via the Chisnantuck, Cottle, and Serpentine Trails. This hike is best in winter and spring when the grassy hillsides of the Bald Peaks are green, although the trail can get muddy after rain. Summer hiking here is typically dry, hot, and unpleasant. This loop is popular with mountain bikers as well as hikers.

I hiked the Bald Peaks Loop in Calero County Park on a nice December day, after recent rains had renewed the green grasses of the hills. Calero County Park lies south of San Jose; I reached the McKean Road entrance by following US 101 south from San Jose to exit 373 for Bailey Road. I headed west on Bailey Road, following it into the foothills of the Santa Cruz Mountains until Bailey Road ended at a junction with McKean Road. Here, I turned left and followed McKean Road south for just under a mile to the entrance to Calero County Park on the right side of the road. Turning right into Calero County Park, I parked at the large, open parking area across from the start of the Pena Trail. Although Calero County Park does charge an entrance fee at Calero Reservoir, there was no fee to park at this trailhead.

I started the loop by crossing the road and taking the Pena Trail, a dirt road trace which was initially flat as it traveled through grassland until reaching a fork with the Figueroa Trail at 0.2 miles. I took the right fork at this junction to follow the Pena Trail up into some gently rolling hills, passing a small manmade pond shortly after the junction. The Pena Trail undulated with the hills until reaching a junction with the Los Cerritos Trail at 0.6 miles; here, the Pena Trail turned sharply and began ascending up an open, grassy ridge. This earliest stretch of the hike was quite muddy during my visit.

Pena Trail winds through grassy hills in Calero County Park

I followed the Pena Trail along its steep ascent up the grassy ridge, with lovely views of Mount Hamilton and Coyote Valley quickly opening up behind me. 

Diablo Range views from the Pena Trail

At 0.9 miles, I came to the junction with the Vallecito Trail; I went left at the junction and took the single-track Vallecito Trail, which descended down a grassy slope to the bottom of a valley and followed a stream through oak woodlands. This was a pretty if ordinary stretch of the hike, particularly nice because it was single track rather than the more common road traces in the Bay Area hills.

Oaks and grasslands on the Vallecito Trail

The Vallecito Trail ended at a junction with the Figueroa Trail, a road trace, at one and a third miles into the hike. I turned left at this junction and followed the Figueroa Trail for a brief hundred meters to reach the junction with the Canada del Oro Trail. Here, I turned right and began to follow the Canada del Oro Trail uphill through oak forest. The Canada del Oro Trail was the first part of this hike’s most extended ascent, climbing 650 feet in just over a mile. The Canada del Oro Trail had no views as the trail was completely in the woods here; the steep incline made this a good and vigorous workout. I came to a fork in the Canada del Oro Trail at 2.2 miles, with the Canada del Oro cutoff trail heading to the left and the Canada del Oro Trail turning to the right. I stayed on the Canada del Oro Trail, heading right and enjoying a short reprieve from the ascent before a final uphill through the forest brought me to the top of an open ridge and the junction with the Bald Peaks Trail at 2.5 miles.

Canada del Oro Trail through the forest

I began to follow the Bald Peaks Trail west (to the right) and the components of this ridge’s lovely views slowly started unfolding. First came views of Loma Prieta, the communications tower-topped summit that is the highest point in the Santa Cruz Mountains and was the epicenter of a 1989 earthquake that caused significant damage and fatalities in the Bay Area. The dirt road trace of the Bald Peaks Trail ran above a small basin holding a seasonal pond that made an interesting foreground to Loma Prieta’s tree-covered form in the distance.

Loma Prieta rises above a pond on the Bald Peaks Trail

The Bald Peaks Trail continued the steep ascent that had started on the Canada del Oro Trail. The trail climbed through most openly meadows with a few scattered oaks, with improving views to the east of Mount Hamilton and Coyote Valley. At 3.1 miles, the trail reached a junction with the Needlegrass Trail coming up from the Rancho Canada del Oro Open Space Preserve. Immediately after this junction, the trail arrived atop a first high point along the Bald Peaks Trail. Views over the next hundred meters of the Bald Peaks Trail, which followed the crest of the grassy ridge, were wonderful. Loma Prieta and Mount Umunhum lay to the west, rising ahead of the Bald Peaks Trail; the view north into San Jose and Santa Clara Valley was unfortunately hampered by some low-level smog but I could see Black Mountain and the rest of the Santa Cruz Mountains marching up the Peninsula. Views to the south encompassed both the Santa Cruz Mountains and the Diablo Range rising on either side of the unseen town of Gilroy.

Mount Umunhum and Black Mountain rising in front of the Bald Peaks ridge

The trail descended from this first high point, reaching a saddle at 3.5 miles where a cut in the hillside revealed some unusually red rock and soil. The Almaden Valley area and the foothills of the Santa Cruz Mountains around Mount Umunhum and Loma Prieta are known for their cinnabar-bearing bedrock. In fact, the nearby New Almaden mine was one of the earliest European-American mining operations in California, preceding the 1849 Gold Rush; decades of mining eventually caused severe contamination of the landscape here, with the Environmental Protection Agency declaring the former mine a Superfund site. Such contamination is not unusual for Santa Clara County, which at the moment has more active Superfund sites than any other county in the United States, most related to contaminants from early semiconductor manufacturing operations by Fairchild and HP.

Leaving the saddle, I followed the Bald Peaks Trail through a short but steady ascent to the second high point of the hike. At a large clockwise turn in the trail, a social path led from the Bald Peaks Trail to the second high point. The views from this point were the most comprehensive of the hike. Looking to the southeast, I had lovely views of El Toro near Morgan Hill dwarfed by the Diablo Range, which led south from Mount Hamilton to a cluster of high peaks in the Hollister area. Loma Prieta stood high to the west and the hazy sprawl of San Jose lay to the north. It really was unfortunate that the day of my hike was so hazy: I’m sure this view would extend to Mission Peak and perhaps all the way to the San Francisco skyline and the North Bay mountains on a very clear day.

Bald Peaks of Calero County Park

Leaving the high point, the Bald Peaks Trail dropped slightly as it headed north and arrived at a junction with the Chisnantuck Trail at 3.8 miles. Here, the Bald Peaks Trail continued to the west, heading into the Rancho Canada del Oro Open Space Preserve. I took the right fork for the Chisnantuck Trail, a single track trail that left the open, grassy ridge crest for the oak woodlands on the north slopes of the ridge. At the junction, there was a bench with a nice view of the San Jose skyline, which was a bit hazy on the day of my hike.

View towards downtown San Jose

Departing from the bench, the Chisnantuck Trail largely stuck to the woods as it descended very gently over the next 2.5 miles. In fact, I found the grade of this trail excessively gentle- which was nice on my knees, but at times felt frustrating because a half mile or more of trail could easily have been shaved off here. In a few spots, the trail emerged into clearings with views towards Mount Hamilton and partial views of Calero Reservoir below. I met quite a few mountain bikers both ascending and descending this trail, so I listened carefully for fast bikers as this was a single track trail with some blind turns.

Mount Hamilton

Grassy oak woodlands on the Chisnantuck Trail

At 6.3 miles, the Chisnantuck Trail emerged into a meadow and intersected with the Cottle Trail shortly afterwards at the Cottle Rest Site, where there was water for horses. The Cottle Trail was a former road trace that followed Cherry Canyon Creek down a canyon towards Calero Reservoir. The Cottle Trail was surprisingly steep, with grades far harsher than anything I encountered on the Chisnantuck Trail as it dropped downhill to the side of the creek, which was flowing nicely during my December visit.

The Cottle Trail emerged into a large clearing and intersected with the Lisa Killough and Oak Cove Trails at 7.3 miles into the hike. I turned right onto the Oak Cove Trail at this intersection; just a hundred meters later, I came to a second junction where the Serpentine Loop Trail split off to the right from the Oak Cove Trail. Here, I once again took the right fork, leaving the much longer Oak Cove Trail for the Serpentine Loop Trail, which returns to the parking lot in a shorter distance. The Serpentine Loop Trail immediately began an uphill ascent, which was broken just two hundred meters in when the two branches of the Serpentine Loop split. I took the left fork, which stayed a little lower but offered some views over Calero Reservoir.

The Serpentine Loop Trail was very muddy, a situation made worse by the cows that had trampled over many parts of the trail. After an initial stretch of uphill through the oak woods, the trail leveled out as it headed east. I came to the Calero Bat Inn at 7.9 miles: this was one of the park’s most unusual features, a small tower designed specifically to provide a daytime shelter for these nocturnal creatures.

Continuing along the Serpentine Loop, I came to a more open stretch of the trail at 8.2 miles, where I caught a couple of rare glimpses of the Calero Reservoir, along with views of the foothills of the Santa Cruz Mountains and of Mount Umunhum.

Calero Reservoir from the Serpentine Trail

Muddy Serpentine Trail

At 8.6 miles, I came to a four-way junction where the Figueroa Trail, the other branch of the Serpentine Loop, and the Pena Trail intersected. Here, I took the left fork for the Pena Trail to return to the trailhead. The Pena Trail began a short but steep climb from the intersection, crossing a grassy ridge and delivering views behind me of Mount Umunhum and Loma Prieta rising over the rolling hills of Calero County Park.

Mount Umunhum rises over the pastoral landscape of the Serpentine Trail

I passed a water tank and the junction with the Los Cerritos Trail at 8.9 miles; I stayed on the Pena Trail, which now began a steep and constant descent down a ridge. At just over 9 miles, the Pena Trail passed the fork for the Vallecito Trail that I had taken that morning to start the loop. I finished up the hike by following the Pena Trail downhill to the trailhead.

Mount Diablo North Peak

View into Livermore Valley

4 miles round trip, 1200 feet elevation gain
Difficulty: Easy-moderate

Access: Paved but windy road to trailhead, Mount Diablo State Park entrance fee required

North Peak is the oft-overlooked shorter sibling to the well-loved and ever-popular main summit of California's Mount Diablo, the iconic double-peaked mountain visible from much of the San Francisco Bay Area. Real estate agents in nearby Walnut Creek once promoted a false claim that Mount Diablo had the largest viewshed of any point on Earth after Kilimanjaro, but the fact that those claims were even somewhat believable gives you an idea of the sweeping panorama from the mountain. While a road leads to an observation tower crowning the main peak of Mount Diablo, 3557-foot tall North Peak is accessible only by hiking and is thus far quieter; although the summit experience at North Peak can be somewhat marred by the extensive collection of telecommunications equipment at the summit, the lovely panoramic views still make this an enjoyable hike. This hike is best in winter and spring, when there is less air pollution and the grassy slopes of Diablo are green.

I hiked North Peak on a clear February weekday, when the weekend crowds that descend on Mount Diablo State Park were absent. The trailhead can be accessed by either the North Gate or South Gate Roads into Mount Diablo State Park, which come from Walnut Creek and Danville, respectively. I arrived from Danville: I left I-680 at exit 39 and followed Diablo Road to the northeast, making a right turn after 0.7 miles to stay on Diablo Road. I followed Diablo Road for another 2 miles and then turned left at the junction for the Mount Diablo State Park Road; signs just before the junction indicated a turn for Mount Diablo State Park and the Athenian School. I followed this narrow paved road through a tony neighborhood before the increasingly windy road entered Mount Diablo State Park; I passed the entrance kiosk and then after 7 miles of driving from the turn on Diablo Road I came to a junction with North Gate and Summit Roads.

Turning right at the junction onto Summit Road, I followed Summit Road uphill for another 3.5 miles to a sharp, eastern-facing switchback just below the summit, where there were wide gravel pullouts on either side of the road. This unsigned parking area is the start of the hike to North Peak. New expanded bike lanes have eaten into some of the parking, but there's still room for ten cars or so to park. If you struggle to park here, you can continue uphill on Summit Road, park in the large lot near the summit of Mount Diablo, and follow the Summit Trail back to the this trailhead.

Leaving from the eastern edge of the switchback on Summit Road, the North Peak Trail led east across the open and grassy south slopes of Mount Diablo. On the very clear day of my hike, the views were absolutely expansive here: closer by, the rolling green grassy hills of Morgan Territory lay below, with the suburbs and shopping malls of the Tri-Valley beyond that and the Diablo Range peaks at Sunol and Ohlone Wildernesses rising beyond Livermore and Pleasanton. To the east, I could see clear across the Central Valley to the snowy peaks of the Sierra Nevada!

North Peak Trail wrapping around Mount Diablo

I followed the North Peak Trail gradually downhill as it wrapped around the south side of Mount Diablo's main peak. At one-third of a mile, the trail came to the southeast ridge of the mountain, a rocky spine leading towards the summit that featured the Devil's Pulpit, an enormous outcrop. Beyond the Devil's Pulpit, I could see all the way to the stone observation tower built atop Mount Diablo.

Devil's Pulpit and the observation tower atop the main summit of Diablo

The southeast ridge also offered sweeping views to the south and west, including some of the best views of San Francisco Bay on this hike. Much of the bay itself was visible, its waters glimmering in the sunlight. The Santa Cruz Mountains rose behind the Bay, with peaks such as Montara Mountain, Black Mountain, and Mount Umunhum clearly distinguishable.

View towards San Francisco Bay and the Santa Cruz Mountains

As the trail turned the corner around the southwest ridge, I found a great view of North Peak. From here, the trail ahead was clear: I could see the North Peak Fire Road that I would later follow running up the ridge of North Peak until eventually reaching the cluster of communications towers at the summit. Beyond North Peak, the watery veins of the Sacramento-San Joaquin Delta snaked across the Central Valley and even further back were snowy Sierra Nevada peaks.

North Peak across Prospectors Gap

After coming around the southwest ridge, the trail descended via a pair of short switchbacks and then entered a forest. Over the next two-thirds of a mile, the trail descended constantly, with more limited views; the final stretch of descent down to Prospectors Gap was quite steep.

One mile from the trailhead and after about 500 feet of descent, the North Peak Trail arrived at Prospectors Gap, a saddle between the main summit and North Peak. Here, the trail crossed Prospectors Gap Fire Road, which led downhill on either side of the ridge; across the road, I connected onto the North Peak Fire Road, which led uphill along a ridge towards the summit.

The North Peak Fire Road was very aggressive in its initial ascent up from Prospectors Gap, with some sections that were quite steep. The first half mile of ascent along the fire road generally stuck to the southern side of the ridge and provided more views out west and south to the main summit and the Tri-Valley. At 1.5 miles, the trail crossed over to the forested north side of the ridge, where the trail flattened out and provided some temporary respite; however, at 1.7 miles, the trail became extremely steep as it tackled the final push to the summit of North Peak. This stretch of the fire road was actually quite tricky to negotiate: gravel covering the fire road made the trail surface loose and slippery and the angle of the ascent was high enough that I was struggling to get traction with my boots. When this short hundred-meter stretch ended, I found myself arriving at the broad-sloped summit area, reaching the base of the telecommunications towers atop the peak at just over 1.8 miles.

The presence of so many towers on the summit certainly detracted from the scenery to a degree; the summit itself was best for views west towards Mount Diablo's main summit and towards the Tri-Valley. Pleasanton Ridge and Mission Peak rose at the far end of the Tri-Valley area, with Loma Prieta's distant but high peak visible behind them. 

Looking back to the main summit of Mount Diablo

View of the Tri-Valley, with Mission Peak and Loma Prieta in the distance

The most enjoyable part of the Mount Diablo North Peak view, however, was found from a small knoll to the northeast of the high point. I followed the fire road counterclockwise around the communications towers and found a social path leading towards a low prominent point along the north ridge. The path died out upon reaching a rockier section of this ridge; there were plenty of rocks here where hikers can relax and enjoy the views to the north and the east.

What lovely views! The Central Valley lay below me, the Sacramento-San Joaquin Delta clearly visible beyond the suburbs of Antioch. The Shiloh Wind Farm- a 500 MW project- was spread out across the delta, which is a wetland of extraordinary ecological diversity. Beyond the Central Valley rose the snowy Sierra. I could clearly make out Pyramid Peak near Lake Tahoe and could see a less distinguishable snowy mass stretching south towards Yosemite National Park. The isolated hills of the Sutter Buttes were visible in the middle of the valley to the north, with the snow-capped and rounded form of Lassen Peak, the southernmost of the Cascade volcanoes, just barely visible.

Suisun Bay lay beyond the nearby suburbs of Concord; a patch of oil refineries dotted the shoreline near the Carquinez Strait. The open pit of the Clayton Quarry is clearly visible, a mountain being deconstructed to make concrete in our cities. Mount St. Helena, Cobb Mountain, and even distant Snow Mountain rose to the north in the Coast Ranges. San Pablo Bay was visible in the distance, with Mount Tam's distinctive profile clearly visible. At the very edge of the view, I could see past the Oakland hills to the Golden Gate Bridge, the San Francisco skyline, and a flotilla of cargo ships waiting to be unloaded at the Bay's many ports.

View towards the Suisun and San Pablo Bays

The Central Valley and the Sacramento-San Joaquin Delta

San Francisco skyline rises behind the Oakland hills

Snowy Sierra Nevada rises over Sacramento-San Joaquin Delta

The view was sweeping enough that for a moment I could imagine that it could be the second largest viewshed in the world, as pamphlets in the mid-20th century claimed. This, of course, was hogwash invented to sell houses in Walnut Creek- Mount Diablo's viewshed is ultimately not even the second largest in California. Still, this was a grand panorama and I was glad to enjoy it all by myself on my hike. Weekends bring far more visitors to this park, so come early or come on a weekday to enjoy the views from Diablo's sibling peak.

Corduroy Hills Loop

The Corduory Hills of Las Trampas Regional Wilderness

8 miles loop, 2050 feet elevation gain
Difficulty: Moderate
Access: Paved road to trailhead, limited parking, no entrance fee required

To Eugene O’Neill- the playwright who became the first American recipient of the Nobel Prize in Literature, who once lived on a farm here in Danville, California- the green grass-covered forms of the Diablo Range in Las Trampas Regional Wilderness were the “Corduroy Hills.” This poetic name is a delightful descriptor of these lovely hills, which are a lush green during winter and spring months and provide enjoyable hiking through grasslands, chaparral, and oak forest with great views of the mountains east of the San Francisco Bay. The hike described here is a loop in the hills directly above O’Neill’s residence, with a lovely ridge walk along Las Trampas Ridge that hits three low summits, grazing cows, and plenty of views of stately Mount Diablo. Winter and spring are the best times to visit, as the hills here are less pleasant during the hot summer months when the sun is overbearing and the grass is brown. The trails in Las Trampas Regional Wilderness can be a little muddy following rainstorms in winter and spring.

The Corduroy Hills Loop can be accessed from several different trailheads; I will describe an approach using the Ringtail Cat Trail from the Ringtail Cat Staging Area on Hemme Ave, although it is also possible to connect with this loop from roadside parking along Camille Ave for a hike of similar distance and difficulty.

I hiked the Corduroy Hills Loop on a lovely and sunny December Saturday, after the first few major rainstorms of the season had already refreshed the greenness of the grass. To reach the trailhead, I took I-680 out to Danville, exiting onto El Cerro Blvd; I headed west on El Cerro Blvd to its junction with Danville Blvd and then followed Danville Blvd north for 1.5 miles to the stoplight with Hemme Road. I turned left onto Hemme Road and drove to the cul-de-sac at the end of the road. There is a small parking lot run by the East Bay Municipal Parks District at the end of Hemme Road that is signed as the Ringtail Cat Staging Area; unfortunately, the lot is quite small and accommodates less than 10 cars. For the moment, street parking along Hemme Road is legal, although I wonder how long the very clearly affluent residents of this subdivision will tolerate the flux of weekend hikers here.

From the parking lot, I followed the Ringtail Cat Trail into the forest along an unnamed creek; while this creek is likely dry for most of the year, there was some low flow during my December visit. The environs around the creek were lush and shaded and the trail was flat. About 200 meters or so into the hike, the trail passed an old pump next to the stream.

Old pump

A third of a mile in, the Ringtail Cat Trail intersected with a trail coming from South Ave. Here, the Ringtail Cat Trail turned sharply to the left and began to climb above the stream. A gradual initial ascent lifted the trail out of the shaded streamside environs onto a grassy ridge with a canopy of oaks; at this point, the Ringtail Cat Trail became substantially steeper as it ascended along the ridge.

Oaks along the Ringtail Cat Trail

At 2/3 mile into the hike, the Ringtail Cat Trail passed a blocked-off side trail leading to the left. Shortly after, the trail left the forest of oaks and broke out into an open, grassy hillside. As the trail continued ascending through two switchbacks up this gorgeously green slope, views of Mount Diablo emerged. As I climbed higher and followed the trail onto the crest of a ridge, more views of Walnut Creek to the north and the Tri-Valley to the south opened up.

Mount Diablo above the grasslands along the Ringtail Cat Trail

Oaks and grassland of the Ringtail Cat Trail

View towards the Tri-Valley

At one mile from the trailhead, the Ringtail Cat Trail ended at a junction with the Madrone Trail. The two directions of the loop split apart here: I chose to hike the loop clockwise, taking the left fork first to handle the steep climb up to Eagle Peak earlier and leave the gentler descent from Las Trampas Peak for the return. This fork of the Madrone Trail- actually a road trace- initially stayed out in the open, providing some more lovely views of the Tri-Valley while passing by a number of stately oaks, but the trail soon (appropriately!) entered a madrone forest and began a steady descent in the woods until emerging on a grassy ridge and intersecting with the Corduroy Hills Trail at 1.5 miles. The Madrone Trail led straight ahead from here down to the Camille Ave trailhead, while a sharp right turn put me on the Corduroy Hills Trail.

Madrone Trail

The Corduroy Hills Trail immediately embarked on a steep and aggressive uphill climb, following a steep road trace uphill through open, grassy slopes with improving views of the Tri-Valley and the luminously green grasslands in the distance. At 1.8 miles, the road trace ended at a small landing, splitting in two to make a small loop (both forks of the loop lead to the next section of trail). From the landing, there were spectacularly open views to the east that encompassed everything from Walnut Creek through Mount Diablo down to the Tri-Valley.

Incomparably verdant grasslands of Las Trampas

The Corduroy Hills Trail transitioned to a narrow single-track trail as it left the landing, continuing to follow the ridge. Here, the grasslands of the lower ridge transitioned to grassy oak woodlands. Over the next 0.8 miles, the trail followed the ridge, with frequent openings that provided many lovely views of Mount Diablo and the nearby chaparral-covered ridges.

View of Danville from Eagle Peak

At 2.6 miles, I came to an unmarked spur splitting off to the left from the Corduroy Hills Trail that followed the ridge to the summit of Eagle Peak. I took this short, fifty-meter detour to enjoy the views from the summit, where there was a nice bench from which I could enjoy the views. Mount Diablo rose high across San Ramon Valley and the sprawl of Dublin and Livermore filled the rest of the Tri-Valley to the south. The barn at Eugene O’Neill National Historic Site was clearly visible in the middle of a grassy field, an idyllic reminder of this landscape’s inspiration on the playwright who wrote A Long Day’s Journey into Night and The Iceman Cometh.

Returning to the Corduroy Hills Trail, I came upon a series of outcrops along the ridge of Eagle Peak that opened up new and lovely views over Bollinger Canyon and across to Las Trampas and Rocky Ridges. Soon after, the trail left the crest of the ridge and descended steeply to a grassy saddle between Eagle Peak and Las Trampas Ridge before climbing steeply up the other side, passing through a narrow hiker gate to join up with the Las Trampas Ridge Trail at 2.8 miles. The southwestern side of Eagle Peak was surprisingly rocky, which added interest to the otherwise chaparral-dominated scenery here.

View of Rocky Ridge from Eagle Peak

At the junction with the Las Trampas Ridge Trail, I turned right and followed the trail to the northwest to continue my clockwise loop. The vegetation along the crest of Las Trampas Ridge alternated between brush and oak woodlands over the next mile. I passed Vail Peak and two junctions with the Bollinger Canyon Trail as I followed the undulating ridge, from which I had superb views of Bollinger Canyon and the rest of Las Trampas Regional Wilderness. Most notable was an open ridgetop walk starting at 3.3 miles, from which I enjoyed amazing views of the Diablo Range all around me. I was even able to spot Mount Tam and the tall conifers on a distant ridge in Redwood Regional Park near Oakland.

View of Las Trampas Ridge and Bollinger Canyon

The trail dropped through another saddle and then ascended again to reach a cattle gate just below the high point of Las Trampas Peak at 3.8 miles. Immediately after crossing the gate, an unmarked social path led uphill and to the left through a grassy slope to the top of Las Trampas Peak. I checked out this short detour, which brought me to the high point of the hike. Las Trampas Peak had nice views down the grassy north slope of the mountain towards Walnut Creek and Suisun Bay; I could spot notable mountains north of the Bay from here, most notably the multi-humped peak of Mount St. Helena. More unique was the view to the west: I could see part of the San Francisco Bay, with the Santa Cruz Mountains rising behind it. While not a remarkable panoramic view, this was still an enjoyable spot to stop.

Santa Cruz Mountains, San Francisco Bay, and the redwoods of the Oakland hills

Returning to the Las Trampas Ridge Trail, I followed the trail down a broad, grassy slope. On this side of the cattle gate, the chaparral of Las Trampas Ridge had been replaced by grasslands, the vegetation here kept trim by the grazing cows. Several cows were scattered across the slope, taking in their daily views of Walnut Creek and its surrounding hills. The trail wrapped around a ridge and passed two unmarked splits in the road trace; the second of these splits was potentially confusing, as the clearer path made a sharp turn to the left even though the actual Las Trampas Trail continued straight. After crossing another cattle gate at 4.5 miles, I continued descending through the meadows until the trail reentered the oak woodlands and arrived at its junction with the Madrone Trail in a small clearing at 5 miles.

View from Las Trampas Peak down towards Walnut Creek and Suisun Bay

Cows grazing the green hills of Las Trampas

During my visit, two cows had made a temporary resting spot out of the junction of the Las Trampas Ridge and Madrone Trails, spreading plenty of their poop around the area. Making my way around them, I took the right fork of the Madrone Trail.

Cows munching and pooping on the Madrone Trail

The Madrone Trail continued the long descent from Las Trampas Peak, sticking mainly to oak woodlands but at one point emerging onto a ridgeline clearing with some more views of Mount Diablo and the Tri-Valley. Making a broad left turn, the Madrone Trail descended until bottoming out at a creek crossing at 5.9 miles. An undulating mile of hiking through the forest after the creek crossing brought me back to the open meadow and the junction with the Ringtail Cat Trail at 7 miles where I had started the loop earlier in the day. A final descent along the Ringtail Cat Trail closed out the hike. 

The Corduroy Hills and Las Trampas Regional Wilderness are already well-loved, but still receive fewer visitors than Mission Peak or Mount Diablo or other overcrowded East Bay destinations. The hiking is just as enjoyable and the views are sweeping, if not quite equivalent to those from taller Bay Area summits. On a nice December Saturday, I saw close to a hundred other hikers on the trail on an all-day hike, although the far reaches of the loop near Eagle Peak and Las Trampas Peak were pretty quiet.

Las Trampas Rocky Ridge

Rocky Ridge and the Diablo Range

5 miles loop, 1100 feet elevation gain
Difficulty: Easy-moderate
Access: Paved road to trailhead, no entrance fee required

Sweeping views of the Oakland Hills, San Francisco Bay, and Mount Diablo make Rocky Ridge the premier hike of Las Trampas Regional Wilderness in California’s San Francisco Bay Area. In fact, short of the most well-known peaks in the Bay Area- such as Mount Diablo, Mission Peak, and Mount Tam- I found that Rocky Ridge had some of the best views in the Bay, its panoramas incorporating the grassy hills of East Bay, the calm waters of the Bay itself, and just about every major peak in the region. This hike is especially nice in winter and spring, when the surrounding ridges and hills are a vibrant green; an additional plus is that this hike, although still popular, sees fewer hikers than Mission Peak or Mount Diablo.

I hiked Rocky Ridge on a sunny but hazy winter day. The trailhead at Bollinger Canyon Staging Area can be reached from either I-580 in Hayward or I-680 in San Ramon; coming from the Bay, I hopped off I-580 at exit 37 for Grove Way and Crow Canyon Road. I followed Crow Canyon Road north for eight miles through Crow Canyon and over the mountains, turning left onto Bollinger Canyon Road at the first stop light after the steep descent towards San Ramon started. I then followed Bollinger Canyon Road north to the end of the road in Las Trampas Regional Wilderness: there was a main parking lot with room for about 40 cars, with parking alongside the road leading to the lot and a secondary lot with room for another 50 cars about a quarter mile back down the road. Las Trampas Regional Wilderness is a fairly popular hiking destination, so expect the main lot to fill on weekends. There was a pit toilet at the trailhead.

Three trails left from the Bollinger Canyon Staging Area: the Bollinger Creek Loop Trail and the Rocky Ridge Trail started from a gate on the north side of the lot, while the Elderberry Trail left from the south side of the lot. I started out the hike on the Rocky Ridge View Trail and would return later in the day on the Elderberry Trail.

The Rocky Ridge View Trail was a paved road (no vehicles allowed) that led steeply uphill from the staging area directly towards the crest of Rocky Ridge; it was ironic to be walking up a paved road in a “regional wilderness.” Climbing 700 feet in three-quarters of a mile, the trail, which was almost completely out in open, grassy slopes, was a good workout. 

Paved Rocky Ridge View Trail leading towards the ridge

Views initially encompassed just Las Trampas Ridge, Bollinger Canyon, and nearby cows grazing the grassy hillsides, but about halfway through this initial ascent Mount Diablo began poking out behind Las Trampas Ridge. Soon, views to the north began improving, too, and by the time the Rocky Ridge View Trail reached a gate about 200 vertical feet below the communications towers on the crest of Rocky Ridge, I could see as far as Mount St. Helena to the north.

Las Trampas Ridge and Mount Diablo

At 0.75 miles, the paved Rocky Ridge View Trail reached a gate that prohibited further entry. The land beyond the gate is administered by the East Bay Municipal Utility District (EBMUD) and is only accessible by permit; the Rocky Ridge View Trail split from the paved road here and over the next quarter mile, it was a pleasant dirt trail leading gently up along the hillside until it reached the crest of Rocky Ridge, just over one mile into the hike. The trail skipped visiting the transmission towers at the top of Rocky Ridge, as those are on EBMUD land; however, there would still be plenty of good views from along the ridge.

Mount St. Helena and Las Trampas Peak

Over the next 1.6 miles, the Rocky Ridge View Trail followed the undulating crest of Rocky Ridge, offering astonishing views over much of the San Francisco Bay Area. Looking west, I was able to see most of San Francisco Bay at many points along the trail, with the Santa Cruz Mountains rising across the Bay. Loma Prieta, Black Mountain, Montara Mountain, and the Sutro Tower were particularly notable landmarks across the Bay; unfortunately, a layer of haze closer to the Bay prevented me from seeing much detail in the San Francisco skyline. Mount Tam was often visible north of the city, the body of the ridge itself blocked many of the views to the north between Mount Tam and Mount St. Helena. Mount Diablo and Las Trampas Ridge made up the heart of the view to the east, while the hazy Tri-Valley to the south was bound by more peaks of the Diablo Range on its far end.

Hazy Diablo Range views

Mount Diablo rises over Bollinger Canyon

Despite its name, the crest of Rocky Ridge is largely grassy, with just minor rocky outcroppings. However, those existing outcrops were worthy of a closer look: the underlying geological formation of Rocky Ridge consists of Cenozoic marine sandstones of the Briones Formation. These sandstones are chock full of fossilized shellfish: take a closer look at any of the rocks along the ridge and you’re sure to spot these densely packed fossils.

Fossilized shells in the Briones sandstone

The trail wandered along the ridge and passed intersections with the Rocky Ridge Loop Trail and the Sycamore Trail around 1.6 miles and then passed a junction with the Cuesta Trail at 2 miles; at each fork in the trail, I stayed on the Rocky Ridge View Trail, which kept me along the top of the ridge, hiking past cows munching on the ridge’s plentiful grasses. 

Cattle grazing on Rocky Ridge

At 2.4 miles from the trailhead, I passed a junction with the Devil’s Hole Trail and then came to a glorious viewpoint on the ridge at the start of an extended descent along the trail. From this position on the ridge, I had a wonderful south-facing view. Rocky Ridge’s grassy crest faded away as it led to the south from here, with the many peaks of the Diablo Range rising beyond. Mission Peak and Mount Hamilton were among the well-known peaks visible from here; I also marveled over the many layers of rolling green hills below me that stretched down towards the Castro Valley area, separating Rocky Ridge from the suburbs of East Bay.

 

View south along the Diablo Range from Rocky Ridge

Oakland Hills and Santa Cruz Mountains

Leaving this lovely viewpoint, the Rocky Ridge Trail descended more steeply, dropping 200 feet over the next third of a mile until the trail made a sharp turn to the left, leaving the ridge and turning into the Elderberry Trail at 2.8 miles. A bench at this sharp turn provided a nice spot to stop and enjoy the ridgetop views a final time.

Looking back at Rocky Ridge

The Elderberry Trail descended steeply as it left Rocky Ridge, dropping quickly into oak woodlands as it headed north. Over the 1.7 miles of trail back to bottom of Bollinger Canyon, the Elderberry Trail generally stayed in the woods, although it broke out into some grassy stretches at times for limited views of Rocky Ridge above, Las Trampas Ridge across Bollinger Canyon, and the top of Mount Diablo on some occasions. At 3.4 miles into the hike, the descent along the Elderberry Trail leveled out a bit and the trail undulated over a series of small gulches; at 4.2 miles, the trail began to descend steeply again, with the downhill ending when the Elderberry Trail arrived at the bottom of Bollinger Canyon at 4.6 miles. Parts of the trail were quite muddy, even two weeks after the most recent rains; frequent use by grazing cows had turned stretches of the trail into muddy nightmares.

Bollinger Canyon and the Tri-Valley

At the corral at the bottom of Bollinger Canyon, the Elderberry Trail intersected another dirt road; the right fork led towards the corral camp staging area while the left fork traveled up the canyon towards the staging area where I had parked. I followed the left fork for a final 0.4 miles along the floor of the canyon, traveling through alternating grasslands and oak woodlands with the gentlest of uphill inclines until I closed the loop at the parking lot.

While the paved portion of the Rocky Ridge View Trail has little to recommend about it, the view-packed traverse along the top of Rocky Ridge makes this hike one of the better outings in the San Francisco Bay Area. Hiker traffic was moderate; I saw over 50 hikers in about three hours, although everyone was spread out and I was able to have many of the nice viewpoints along the ridge to myself. Pick a clear day when the hills are green to enjoy the views on Rocky Ridge in Las Trampas Regional Wilderness.