Having the Marin hills practically on our doorstep means never going too far to find a hiking trail. But the vast network of trails and fire roads also means a hike could have no end unless you pinpoint a goal of your own making.
Big Rock Trail in Lucas Valley makes that decision easy because it takes hikers to the second-highest peak in Marin, trailing only Mount Tamalpais. And that peak is easy to find because it’s topped by radio towers that are visible from the trailhead and from many other vantage points in the northern part of the county.
Making it to the towers gets you a 360-degree view of Lucas Valley and Ignacio Valley from Big Rock Ridge, which rises between the two.
The trailhead is easy to find. Just take Lucas Valley Road about 5.5 miles west from Highway 101 until you see a big rock on your right. The rock itself is on private property. Just across the way is roadside parking, but making a U-turn if you’re westbound is tricky because it’s a bit of a blind rise for eastbound drivers. You can go a little way down Lucas Valley Road and turn around more safely, and then park near the trailhead on the south side of the road.
A tunnel that is home to many swallow nests runs under the road and connects the Loma Alta Fire Road on the south side to Big Rock Trail on the north side. Go through the tunnel, heeding signs that ask for quiet for the sake of nesting swallows. When you emerge, you’ll be on Big Rock Trail. Because this is Marin, there will be cows. And because this is Marin, there will also be views.
The trail is about 6.5 miles round trip, an out-and-back journey. About a 1.5 miles in, as the path climbs gently upward through rolling grassy hillsides, you can look down on Skywalker Ranch on your left. Keep moving forward as the trail narrows to single track at some points, crosses a couple of bridges and relies on switchbacks to carry travelers to the top. The trail forks in some places where hikers have clearly taken shortcuts, but signs ask users to please stay on the main pathways.
Toward the peak, the ridge runs east–west. Heading east will take you to the radio towers that top out the Big Rock Trail. From this vantage point, you can see Ignacio Valley to the north and look down on Lucas Valley to the south.
I swear I also caught glimpses of the Nicasio reservoirs while descending Big Rock on a recent Sunday. That day, we encountered few travelers, but because the trail is multiuse. Users on foot would do well to keep an ear out for cyclists, especially on the trail’s narrower parts with limited sight distance.
Big Rock Trail tops out at about 1,800 feet, much shy of Mt. Tam’s 2,579 but still affording striking views. From the Lucas Valley trailhead, you’ll gain about 1,100 feet in elevation. It’s not a strenuous climb, but it’s a continuous one, just enough to get the heart rate rising steadily for the upward portion.
We got lucky on our last outing because a small gopher snake favored us with its presence just as we approached the towers. The usual mix of bay, oak, coyote bush and manzanita will be familiar to aficionados of the Marin hills, and bird enthusiasts will find plenty to tweet about if they keep on alert.
It’s crispy and parched in the hills as September continues the dry march of summer, but the day of our hike was cloudy and cool, a welcome respite from the recent heat wave. As we made our way down, the layers of sky and clouds in the west took on different hues with the approach of sunset, and we encountered only one other hiker along the way.
• Getting there: Take the Lucas Valley Road exit from 101 and head about 5.5 miles west, keeping an eye out for a big rock on the right, just as the winding road emerges from the trees. Dogs are allowed on this trail, as are bikes.
Emily Willingham is a Marin science journalist, book author and biologist. You can find her on Twitter @ejwillingham.
Source: www.mercurynews.com