Cross over to Bridge Spring

The Eldorado Mountains flank the western side of the Colorado River's Lake Mohave just south of Boulder City. Well-known for four-wheel driving opportunities, the area also contains roadless stretches that are a hiker's paradise, unspoiled and rarely explored. Yet most of it is within easy reach, even if your only transport options are low-clearance sedans and shoe leather.

A good way to familiarize yourself with this area is hiking to Bridge Spring. This is a fairly easy journey of just two miles, round trip. If you take the main route, the travel distance and elevation gain are minimal, so it is appropriate for children, but they will need to do some rock scrambling, and you'll have to beware of some drop-offs once you near the bridge.

Natural bridges are rarer than arches, because the former, by definition, spans or at one time spanned a waterway, the water being in some way responsible for forming it. In this case, a spring-fed stream runs only a short distance, and breaks up into occasional pools and puddles. But it waters plants and creates animal habitat that otherwise wouldn't be present, adding to the interest of the place. Just going to the bridge and back makes an excellent outing, but for more adventure you can easily turn a trip here into a full day of exploring.

From the trailhead, head east up the faint trail to the ridgeline. From here you'll be able to catch a glimpse of Nelson, a colorful old mining town which lies about a mile south. Continue on, making many gentle ascents and descents along various ridges. After about a quarter-mile the trail drops into a well defined wash, which serves as your route for the remainder of the hike.

Hiking this drainage is pretty straightforward, although occasionally you will have to skirt some obstacles, such as pour-offs and rocky areas. Keep an eye out for interesting formations, like windows in the rocks and one stunning 25-foot corkscrew run-off. Winter brings its own charms; look for small pools of water, often frozen this time of year, and if it's cold enough you'll notice small icicles that hang delicately from water seeps.

If you have the time on your return, head up the spur canyons, all well worth the trip. Some are just short and box-like, where without good climbing skills your progress will eventually be blocked. Others are passages so tight that if you reach out, you can easily touch both sides at the same time, which makes them especially fun to walk through.

After about one-half mile, on the right side of the drainage, you'll come to a boulder about 25 feet tall and 15 feet wide, which seems to balance there as if defying gravity. It appears that if you leaned against it, it might fall. After this, the wash becomes more lushly vegetated, mainly with vigorous scrub oaks, some of which grow as tall as 20 feet.

A little farther on, look up to the high cliff on your left and you'll see the large entrance to a cave. It is accessible, but a 100-yard climb up a tricky scree slope and the unstable scree makes for a dangerous return descent. The inside of this grotto is about 20 yards long and the ceiling in places rises up about 15 feet. At the far end it has a natural opening just big enough to fit a human or large animal, which could make a handy escape route if some danger came in the front door.

Because of the nearby spring, this is an important area for wildlife. Some of the more interesting creatures that call this area home are bighorn sheep, chuckwalla lizards, bats, rattlesnakes and even the elusive Gila monster. This monster, actually a one- to two-foot-long poisonous lizard, should be hibernating this time of year, but come springtime you might encounter one. If you're so fortunate, you'll recognize its colorful pattern of black with prominent splotches of orange, pink or yellow. The habitat here is an ideal one, for they prefer damp rocky desert areas.

As you continue down the wash, the vegetation becomes dense, with lichen and moss colonize on many boulders, and you'll notice more water along the route. Keep an eye out for the well-worn wildlife trails that run up the grassy areas leading to a broad canyon on your right.

As you get closer to the bridge you'll find a few obstacles in the way -- boulders that you have to carefully scramble down and thickly vegetated areas. Once the bridge comes into view, stay left against the canyon wall for the easiest way to reach its base. The bridge spans about 30 feet, joining the two canyon walls with a 15-foot-thick rib of rock. There's plenty of room to stand underneath; the clearance seems about as high as the bridge is thick.

If you continue downstream past the bridge, the canyon becomes steep and is choked with boulders. Here though, is one of the few places that afford passage up to the top of the left cliff. You won't find it an easy climb but for those who can make their way up, there are incredible views. You'll be able to see down Eldorado Canyon, about seven miles to Lake Mojave, and as far as Mount Tipton, 40 miles away, just south of Dolan Springs, Ariz.

We went there and back again in under a day, but found so much to do and see it could easily have occupied us from dawn to dusk. Not a bad adventure to start a bare hour from the city, via a trailhead easily accessible from a good paved road.

Deborah Wall is the author of "Great Hikes, A Cerca Country Guide," published by Stephens Press. She can be reached at Deborah@hikingthewest.com.