"Shush," the hiker coming down the trail whispered. Bighorn sheep were just ahead, he said, and we could see them if we walked quietly.

A few steps farther along the trail and there they were: a ram and six ewes, busily nibbling on whatever they could pull from the sandy brown desert floor. We approached the sheep on tiptoe, fearing they would bolt and disappear into the canyon's innumerable hiding places. But they stood their ground, warily watching us as we madly snapped pictures.

The sheep were where we least expected them, just a few dozen yards from the start of the most popular hiking trail in the Anza-Borrego Desert State Park in Southern California. A sign at the trail head said the peninsular bighorn (a rare subspecies of the mountain sheep found in much of the West) were extremely shy and likely would be seen -- if at all -- only at a great distance as they clambered over mountain ridges overhead.

Even close up, from less than 30 feet, the deer-size bighorn tends to fade into the background. Its brownish gray coat perfectly matches the boulders, the ground and even the vegetation of the desert. It stands out clearly only when seen in relief against the blue sky.

Ambling through a dry stream bed alongside the trail, our sheep headed toward the distant palm trees we had come to see. We followed them into the canyon at a leisurely pace for more than three hours, never sure when they would tire of human companionship. Finally, after picking over the greenery at the relatively lush Borrego Palm Canyon, the sheep headed up the side of Indianhead Mountain, seeming almost to fly over shoulder-high boulders and stands of cactus.

These were our first hours in Anza-Borrego, 600,000 acres of desert valleys and mountains about 80 miles northeast of San Diego and 80 miles southwest of Palm Springs. For the next several days we hiked and drove over much of the park, but we never had another glimpse of the bighorns, called the borrego in Spanish.

"Anza" comes from Juan Bautista de Anza, captain of an expedition that passed through the desert early in 1776 on the way to establish a Spanish colony at San Francisco. Ever since, this area, like all deserts, has been a place for most people to pass through rather than a destination in itself.

But as first-time visitors, we found Anza-Borrego a place of great beauty, blessedly uncrowded and only marginally spoiled by all-terrain vehicles, burger cartons and other modern paraphernalia. Although it's the biggest state park in the West, Anza-Borrego is well-known only in Southern California and draws few out-of-state visitors. More famous deserts in the Southwest -- the Mojave and the Sonoran, for example -- are bigger-name attractions for those wanting winter sunshine away from the beach. But Anza-Borrego provides an excellent contrast for visitors to San Diego who want to supplement the standard itinerary of zoos, beaches and Tijuana.

The park surrounds Borrego Springs, a sprawling resort and retirement community (year-round population 1,405) hemmed in by the Santa Rosa and San Ysidro mountain ranges. Local promoters and developers over the years have tried to transform Borrego Springs into a Palm Springs South, and their efforts have produced a handful of motels, restaurants and tourist-oriented shops. But the speculators have not yet created a Gold Card oasis in this desert.

Aside from enjoying the sunshine, the chief activity in Anza-Borrego is exploring the results of the ages-long transformation of a sea floor into a desert and man's more recent arrival. From the crest of the lush Laguna Mountains just to the west, the desert appears as a chalky wasteland, forbidding and unbearably hot, even in winter. But the slow, winding descent into the valley along State Route 78 presents a different picture. Clumps of cholla cactus and fields of thistle and wild buckwheat prove to the skeptic that some living things do thrive in the desert. On the outskirts of Borrego Springs, deep wells tap natural underground reservoirs for the water that feeds four golf courses and hundreds of acres of citrus trees.

The desert's contrasts perhaps can best be seen at two locations off San Diego County Route 2 (the Imperial Highway) in the southern part of the park.

At the Mountain Palm Springs campground, trails lead west into canyons sheltering six distinct groves of California fan palms. Among them, Pygmy Grove features stunted trees only about half the normal 80-foot height, and Surprise Canyon proves true to its name, with dozens of trees making a dramatic appearance as the trail leads into a natural spring-fed opening in the mountains.

Just four miles down Route 2, the road crests Sweeney Pass, revealing a broad view of the Carrizo Badlands. Some of the oldest and most dramatic rock formations in the park can be seen here at a convenient turnoff. For a closer look, a hike of less than a mile takes you into Canyon Sin Nombre (Canyon Without a Name), where layers of rock have been twisted and tilted over the ages into enormous S curves. Much of the badlands is posted off-limits; it is the Carrizo Impact Area, a former Navy bombing range said to be littered with unexploded shells.

For the most part, signs of human intervention in the desert are at roadside or at the end of short trails. At the aptly named Foot and Walker Pass, the trail was so steep that passengers on early stagecoaches had to get out and walk or help push. Nearby, a pleasant hike through a garden-like canyon of rocks and cactus leads to the pictographs -- red and yellow figures painted on giant boulders by Indians hundreds of years ago.

A more whimsical monument to human activity is the memorial honoring "Pegleg" Smith, teller of tall tales, who claimed to have discovered gold in the desert valley around 1829. Pegleg might have described the monument, at the base of Coyote Mountain, as a magnificent pyramid rivaling the burying places of the Pharaohs. Those of us who lack his gift of hyperbole might instead see it as pile of desert stone, to which the seeker of gold is invited to add 10 rocks. Even so, Pegleg's spirit lives on at this site. The annual Pegleg Smith Liar's Contest takes place here the first Saturday of every April. Stories told at this event are allowed to contain nothing resembling the truth.

In addition to enjoying the story-telling heroics of modern Pegleg Smiths, early spring is the time to see the desert wildflowers in bloom. In normal years the three or four inches of winter rain produce an explosion of color in March and April -- yellows from the spiky agave and scarlets fro the ocotillo bush among others.

Most of the flowers quickly give way to the heat of late spring, and by June the 100-plus temperatures of midday once again have turned the desert into a rich variation on the theme of brown.

Late fall and winter are the other rewarding seasons for a visit to the desert without the stress of triple-digit temperatures. By late October or early November the daily highs fall into the 80s or 70s, and nights are cool and crisp.

On a warm November day, we drove up the hairpin turns of Montezuma Grade, carved from the side of San Ysidro Mountain, starting our return to San Diego. We stopped at the Culp Valley campground for a look back at the Borrego valley, hoping also for a last glimpse of bighorn sheep.

We already had filled our bighorn-watching quota, of course, but we were rewarded with a spectacular mountainside view of the desert valley stretching east to the Chocolate Mountains. We also discovered Pena Spring, once an important watering hole for cattle and now reserved for the wild creatures of the desert.

Walking through the greenery fed by the cool spring, we were startled by the sudden swoosh of a dozen or so California quail taking off from the bushes. It was a final reminder that this desert was not the wasteland we thought we had seen from afar.

WAYS & MEANS GETTING THERE: Anza-Borrego Desert State Park is about 80 miles northeast of San Diego. From San Diego, take Interstate 8 east to Highway S2 at Ocotillo; take S2 north to Highway 78, then east to Route S3 and into Borrego Springs. The park's visitor center, two miles west of town on Route S22, provides an excellent orientation, with desert displays and exhibits, a 25-minute slide show, guidebooks and maps. CAMPING: Anza-Borrego Desert State Park maintains campsites at several locations. Two (Borrego Palm Canyon and Tamarisk Grove) are fully developed, with showers and restrooms; the others are more primitive. Reservations, by credit card, can be made by calling 1-800-444-7275. Unlimited open camping is also permitted, at no charge.

Several public and private campgrounds have recreational vehicle hookups. Among the larger are Butterfield Ranch (619-765-1463), Overland Junction (619-767-5341) and Agua Caliente Springs County Park (619-565-3600). WHERE TO STAY: La Casa del Zorro (3845 Yaqui Pass Rd., P.O. Box 127, Borrego Springs, Calif. 92004, 619-767-5323 or, from outside California, 1-800-325-8274), a romantic, Spanish-style resort built in the 1930s, is the area's premier resort, with swimming, tennis and golf. Rates for a one-bedroom apartment start at $47.50 in summer (June through October) and $95 in winter (November through May), daily.

Overland Junction, a new development at the west of town near the visitors center, features a motel, restaurant and shops (619-767-5341). Other motels in the area are the Stanlunds (619-767-5501), Desert Ironwoods (619-767-5670), Hacienda del Sol (619-767-5442), the Oasis (619-767-5409) and the Whispering Sands (619-767-3322). Rates start at about $40 per night, double. INFORMATION:

Anza-Borrego Desert State Park and Visitors Center, P.O. Box 299, Borrego Springs, Calif. 92004, (619) 767-5311.

Borrego Springs Chamber of Commerce, Box 66, 622 Palm Canyon Dr., Borrego Springs, Calif. 92004, (619) 767-5555.

John Felton is a Washington writer.