Fresh Tracks: Satisfying maze of single-track found at Fairfield’s Rockville Hills Regional Park

Someone once told me – or I read it on a blog, or I heard it secondhand on the trails, but, in any event, I now accepted it as truth – that Rockville Hills Regional Park’s glorious 600 acres once, long ago, were slated to be developed as a golf course.

As if we really needed another one of those.

Instead, the city of Fairfield kept this hilly expanse on the west part of town wild and free of manicured greens and portly guys in loud polyester outfits riding around in electric carts.

What we have instead is a maze of trails, ranging from lush and challenging single-track to wide and accessible fire roads, that arguably is used by a far greater percentage of the population – mountain bikers, hikers, trail runners, dog walkers, picnickers – than those willing to shell out fees for a round of what Mark Twain once called a good walk spoiled. Plus, it would’ve been a shame to bulldoze out all the geologically interesting boulders and volcanic rock that line the trails like confetti for the sake of smooth fairways.

The great thing about spending a few hours at Rockville Hills, be it on foot or pedaling on 26-inch tires, is that you’re never bored. There’s always another hill, short and steep, beckoning. There’s always another side trail tempting you to make a diversion. There’s always another shady blue oak providing a spot for a pleasant respite. There’s even a lake smack dab in the middle of the park, lined by picnic tables.

And, most prominently, there are rocks. Rocks galore, lining the ridges and spread across the valleys, rocks overtaking some trails to such extent that navigating becomes something of a puzzle.

Such technical paths are why Rockville is one of the most popular mountain bike trails in the Bay Area – save Marin County, cradle of mountain bike culture, of course.

“Finding good technical trails with rocky features are hard to find, especially in the East Bay,” said Dennis Baker, who travels all the way from his home in Stockton to ride Rockville regularly. “I mean, there’s a fair amount of ugly, cow-riddled, eight-feet-wide fire roads, but actually single-track is hard to find.

“Bikers like the variety. It’s really choppy. You grunt up something and get this little technical challenging downhill, then you can loop back around and ride that again. There are a few trails at Rockville that are more challenging than what’s available out there anywhere.”

Which is why the parking lot off Rockville Road, about a 10-minute drive off Interstate 80, is filled with cars with bike racks most days.

To some hikers and trail runners, the specter of scores of mountain bikers gunning down trails is off-putting. Fear not, though. I’ve been to Rockville a half-dozen times since September and I’ve only been passed by a speedy rider once or twice (and they were exceedingly friendly and respectful of those on foot). That’s because the mountain bikers gravitate to the trails with the most extreme, technical, jaggedy features, such as the gnarly and aptly named Rock Garden Trail, 0.4 of a mile of kidney-jangling fun.

So if you stay away from the bikers’ hangouts, you won’t face any potential trail conflicts. And, with at least 25 trails listed on the regional park’s map and several other unofficial offshoots, you shouldn’t have a problem avoiding a critical mass of cyclists.

All these trails have a downside, though. Namely, you can get lost easily. The trail signage is sometimes spotty, so this is one trek where it might be good to bring a map. You can search and download a detailed one at or get a topographical map at the trailhead kiosk. I had an inkling that Rockville might be difficult for the directionally challenged when I read the blogger Bay Area Hiker’s assessment: “You may find that Rockville is best experienced if you give up any semblance of control and just wander around.”

I grabbed a map and marked out a 6-mile circuitous loop that pretty much circumnavigates the park and mostly gives a wide berth to mountain bikers on the Rock Garden Trail. Embarrassing to say, though, it took me four times before I successfully negotiated the trail without taking a wrong turn and adding mileage. Not that there’s anything wrong with adding mileage, but wandering around not knowing if that next trail junction is going to lead you farther down the rabbit hole can be disconcerting to some. My main problem was that some of the connectors to the major signed trails aren’t marked (or are confusingly marked). That’s my story and I’m sticking to it.

But the park is so compact that you eventually will reach high enough ground that you can see the trailhead, as well as pretty sights such as Mount Diablo in the distance. Along the way, you’ll pass by scores of oak-studded hills, lots of manzanita and toyon, enough to cancel out the long-distance sights down in the canyons outside park territory – subdivisions.

The first half-mile of the trek is north along the Lower Quarry Trail, where you get an immediate lesson about the geologic features of the park. After a few hundred yards, you must ascend a slab of boulders with all the dusty ground cover worn away. It can be slick even in dry conditions but, again, that’s part of the fun. The Lower Quarry is mostly single-track, twisting through trees and manzanita bushes. Whenever there’s a trail junction, signed or unsigned, just keep bearing right toward the fence line. Eventually, you’ll hit a paved road. Cross it and join the signed Unknown Trail, its name probably someone’s idea of wit.

What’s known about the Unknown is that it remains mostly single-track with rocky sections and some rolling climbs until you reach a series of four switchbacks that will test your ascending ability. Yes, mountain bikers sometimes frequent the Unknown Trail, but I saw none on this stretch on several trips.

Once you reach the apex of the switchbacks, the confusion begins. You want to follow the Jockey Junction Trail for maybe 0.2 of a mile, and there are signs for it. That is, until you reach a valley where trails fork in several directions. Where you want to head is south. Look for signs pointing toward the Mystic Trails.

Now, there are several Mystics out there. Don’t take the Upper or Ridge trails. Either the Lower or Middle will lead you to the Black Oak Trail, which encompasses a big chunk of our route. I chose the Lower because, frankly, it looked more downhill, but eventually you’ve still got to climb a switchback to get to the Black Oak Trail, where you make a right. The Black Oak is tree-lined and grassy and mostly flat, a nice change from the up-and-down of the Unknown.

It dead-ends at the Green Valley Trail, which leads to the major climb of the trek. You turn a corner of a hillside after a moderate climb and immediately start climbing steeply toward an electricity tower in the distance. It seems like forever until you reach said tower, but you’re rewarded with a nice, smooth downhill on a fire road leading to the lake.

You stay on the fire road as it curves around the right side of the lake and pass a “pond” that was bone-dry in late September before reaching a paved road. Follow that to the right until you reach a connector to the Lower Tilley Loop. Follow Tilley around the mountain for 1.3 miles of single track until turning right on a trail called Devil’s Backbone – a rocky downhill, followed by smooth single track – back to the starting point.

I almost, almost, gave into temptation along the Lower Tilley and made a side trip on a trail not charted on the map. The sign at the junction called it “The Outback,” and it looked as if it was going to lead into the nether lands.

So I took the easy way and cruised back to the trailhead, where more mountain bikers were unhooking bikes with fat tires from their roof racks. Sure beats golfers with spare tires around their waists taking clubs out of their trunks.


Read the finer details about Rockville Hills, and see more pictures and a map, on Page D3.


To view a gallery of photos by Randy Pench, go to


2149 Rockville Road, Fairfield

Distance: 6 miles.

Directions from Sacramento: Take Interstate 80 west to the West Texas Street/Rockville Road exit. Follow Rockville Road west for 3.6 miles to the trailhead on the left.

Parking: Free.

Cost: $3 per person; $1 for dogs.

Route: From the trailhead, go right (north on the Lower Quarry Trail until it dead-ends at a paved road). Go right onto the Unknown Trail for about 1.5 miles, staying to the right at trail junctions. After ascending switchbacks, join Jockey Junction Trail for 0.2 miles, looking for signs for the Mystic Trail. Take the Lower or Middle Mystic Trail to the Black Oak Trail, where you will turn right. Black Oak dead-ends at the Green Valley Trail. Turn left and ascend to a fire road leading down to the lake. Take the fire road on the right side of the lake to a paved road. Go right on the paved road to a connector to the Lower Tilley Loop. Follow the Lower Tilley to the Devil’s Backbone junction. Turn right and go about a mile back to the trailhead.

Difficult: Moderate.

Elevation: 1,093 feet.

Exposure: Partially tree-shaded, except on the Green Valley Trail.

Toilets and water: Not at trailhead.

Poison oak possibility: Moderate, but check for ticks afterward.

Probability of getting lost: Good, so bring a map, but know that the park is small so you won’t get hopelessly lost.

Will there be blood? Take is slow in those jagged rock gardens.

Dogs: Must be leashed.

— Sam McManis