The most convenient jumping-off place for a visit is the town of La Pine, named for the ponderosa pines surrounding it. Southeast of town, off Highway 31, you'll see the first of the area's geological oddities: a 450-foot-deep crater known as Hole-in-the-Ground, the remains of an ancient volcano. But an even more dramatic landmark lies just beyond: a semicircular wall of rock rising more than 300 feet from the desert floor. Fort Rock State Monument—its steep walls resemble a fortification— was once a wave-lashed volcanic island in the ancient lake. "You can still see where waves and wind scoured the rock over many centuries," says Curtis Smith, who leads tours of the area for the Oregon Parks and Recreation Department. From the visitor center a trail leads inside the caldera and up onto the rim, offering panoramic views of the arid land below.

Within sight is the shadowy mouth of Fort Rock Cave. Revered by American Indians, the cave is also an archaeological site. Here, in 1938, University of Oregon scientist Luther S. Cressman unearthed some 75 woven sagebrush-bark sandals estimated to be about 10,000 years old. "The sandals are among the oldest footwear found anywhere in the world," according to Dennis Jenkins, an archaeologist at the University of Oregon. Some lay under volcanic ash, evidence that people lived here when the massive volcano that created Crater Lake erupted, blanketing the region and choking out aquatic life. Although cave access is restricted, tours can be arranged with the Oregon Parks and Recreation Department.

Reminders of much more recent human inhabitants are on display at the Homestead Village Museum in the town of Fort Rock, where nine buildings from the early 1900s have been gathered. They include several houses, a two-room doctor's office (with shelves of tonics), the post and land office, and St. Rose Catholic Church, built in 1918. Together, they give a vivid impression of what life was like for the pioneers.

East of Fort Rock, an unpaved road leads south past a quartet of graceful volcanic cones. Snaking between them, the low rounded ridges of ancient lava flows make it look as if a giant beast had burrowed underground. Just beyond a parking area, a quarter-mile trail leads to Crack-in-the-Ground, the spot where the earth split and left the gash that still looks raw today. You can walk down into the rift, squeeze between its sheer rock-lined sides, and gaze up at a narrow sliver of sky.

Much of what paleontologists know about the prehistoric animals that roamed the outback comes from discoveries made at nearby Fossil Lake. Here, researchers have found bones from flamingos, camels, and mammoths. Visitors can park and explore the area. To the east is a vast expanse of dunes made not of sand but of ash from volcanic eruptions.

By the dunes to the northeast an isolated cluster of ponderosa pines called the Lost Forest thrives improbably in the desert, a holdover from an era when the region was dense with pines. "Most ponderosa require 14 inches of annual rainfall," says Lucile Housley, a botanist with the Bureau of Land Management. "These get by on less than 10." Although scientists don't fully understand how the trees survive, they think the sandy soil helps make the scant water more accessible.

On a day trip from La Pine you can hit the main sights and still have time for the Cowboy Dinner Tree Steakhouse, a rustic, family-style restaurant that serves portions of barbecued chicken, beef, baked potatoes, and homemade bread big enough to satisfy the hungriest ranch hand after a day in the saddle. To dig a little deeper into the region's history, spend a few days. A good place to hang your hat—basic but conveniently located in the middle of Fort Rock Basin—is the Lakeside Terrace Motel in Christmas Valley. From here, head south along the Outback Scenic Byway, which leads past stately Table Rock, Summer Lake, and Warner Wetlands.

These days, Oregon's outback is home to cattle and horse ranchers. Many are descendants of homesteaders who came here expecting to farm this land. The arid climate dashed those hopes, but some families found ways to stay on. When you get to know the outback, you'll understand why.