Once a province of the improbable, practiced by mythopoetic men, the likes of Edmund Hillary, Jacques Cousteau and Thor Heyerdahl, "adventure travel" was something seen in the pages of National Geographic, not available to the average Jane or Joe. The only adventure travel on Main Street was when a well-planned vacation went wrong.

Now, with the prospering of a generation steeped in environmentalism, self-health and individualism, adventure travel has become the vogue. By one survey, fully half of all U.S. adults took an adventure getaway within the last five years.

I've spent a career exploring and adventuring, and am always delighted to rediscover how varied and rich the adventure opportunities are in my own back yard. You don't have to cross a border to find some of the best adventures in the world.

The adventures cited below were chosen because they have personally delighted. It is unfair — to say nothing of impertinent — to list only a small percentage of the great adventures in America. But that is the nature of a list. I have attempted, though, to use criteria, including location, duration, activity, and a quality I might as well call wonder.

So, herein is a list of the 10 best adventure vacations in America, scientifically calculated with subatomic precision by yours truly:

Llama Trekking the Hoover Wilderness Area
California's High Sierra is a toothed landscape of lodgepole pine and red fir, arid desert, U-shaped glacial valleys, a place of solitude and spectacle. The Hoover Wilderness is 42,800 acres of primitive country in the east-central part of the state, touching Yosemite National Park at the Sierra Crest. This adventure features a five-day trek among the sagebrush and thistle, the escarpments and the late summer snow fields, as South American llamas carry the cargo. Expect to see mule deer, and perhaps bobcats, coyote, bear and maybe even a mountain lion. The streams choke with trout, while the high peak region — including Matterhorn and Dunderber (each over 11,000 feet) — host schools of technical and amateur climbers. A llama can carry 70-90 pounds and doesn't have to carry extra food for itself. Llamas are browsers, like deer, and will eat grass found in the mountains. Llamas are very quiet, very friendly to the environment and do not destroy trails. August is the best month.

Adventure Sailing Florida's Gulf Coast
Sail aboard 26-foot Commodores through the small islands off Fort Myers for seven days and nights in flotillas of up to six boats at a time. The crafts are designed for four adults, and qualified sailors can captain their own craft for the duration. Lots of time to free sail, and explore the tropical barrier islands inhabited only by gulls, pelicans, and man-of-war birds. Dolphins lace the bow, red snappers snap at the lines, living shellfish color the limpid waters, and Gulf breezes fill the foresails. Fort Myers is on the Southwestern coast of Florida near Sanibel and Captiva Islands, 120 miles south of Tampa and 110 miles north of Key West and the Dry Tortugas. Available year-round.

Kayaking the San Juan Islands
Scattered like precious jades within the sheltered waters of Washington's coastal zone, the San Juan's are treasures not so hidden, yet not overly touched. In waters flat as a Bible belt, the boats glide like a prayer. Bald eagles swoop to scan the emerald waters; orcas dance and dine in the salmon-laced tides; scaups and scoters drive for fry near the forested isles. Sea kayakers meet them all, eye to eye and beam to beak. No previous experience needed. June-September.

Canoeing the Boundary Waters
The Boundary Waters Canoe Area Wilderness, largest in North America, has over 1,500 icy, clear-water lakes accessible by paddle only in an area of well over a million acres, unchanged since when the Sioux, Chippewa and French-Canadian voyagers navigated through hundreds of years ago. Every fall from about 1750 until the mid-1800s, the Voyageurs carried trade goods through the Boundary Waters as far as the Great Slave Lake in Canada's Northwest Territories. They spent the winter in the interior trading with the Native Americans. When the ice went out of the lakes and rivers, they returned with beaver and other pelts. In fact, the Voyageurs' route through the Boundary Waters defines the Canadian-U.S. border. Trips begin at Gunflint, Minnesota, and head out for six days of paddling and portaging. Canoeists typically encounter moose, beavers, black bear, eagles, loons, otters, and timber wolves, the last large packs in the lower 48 states. Fishing lines bring in walleye, northern and lake trout, as well as smallmouth bass. May through September.

Mountain Biking the Grand Staircase
Between the pink cliffs of Bryce Canyon and the sheer walls of the Grand Canyon's north rim, an expansive geological staircase climbs skyward in rainbow pastels. Through the vast wilderness of remote-forested mesas and flamboyantly-stained buttes flows the Paria River, whose waters, cutting unceasingly through layers of sedimentary rock, have formed some of the finest slot canyons in the world. On this adventure fat tires float through the sinuous yet spacious backcountry of the upper Paria, which flows out of Bryce Canyon. After descending Echo Cliffs and rumbling along dirt roads to the rim of the Grand Canyon, the bikes climb from sagebrush valleys to groves of pinon to tall ponderosa pine forests following jeep trails into the Kaibab Mountains, where vestiges of the Anasazi culture are ever-present. April through July.

Climbing Denali
An ascent up the west buttress of Denali, North America's highest point, is no slick adventure tour, as there is no easy way up. An outfitted climb takes about three weeks on the mountain, living and climbing in true expedition style. Base camp is set at 7,000 feet on the tongue of Kahiltna Glacier, and from there relay loads are made over the course of a week to the 14,000-foot level, and finally to high camp at 17,200 feet. Then the team waits — for the crystal clear morning when the wind is still and the horizon line sharp and the snowy route to the summit firm. The final push to the 20,320-foot apex makes the most of mountaineering skills honed while on the climb. Although previous climbing experience is helpful, it is not essential. Far more useful is the physical and mental health necessary to cope with the long days of glacier travel, the snow and ice climbing, and the possibility of poor weather delaying, or perhaps canceling, the summit attempt. April-June.

Riding the Tetons
Sally along the edge of the Continent Divide through the lush meadows and pine forests of the Snake River canyons, passing herds of elk and bighorn sheep. Pause to fish for cutthroat trout in the clear blue waters of Jackson Lake, glancing about for beaver, otter, osprey and moose, and perhaps even the recently-reintroduced gray wolf, all enjoying protection of the National Park. Then meander along the Buffalo River, through aspen forests to open meadows, where brilliant wildflowers and awesome views abound. Traveling this way, you'll regret the invention of the car. July and August.

Hiking Hidden Hawaii
Step through the natural wonders of Kauai, an island so diverse in color, mood and miracle that one wonders what keeps the feet on the ground. Traverse the mottled and multi-hued cliffs of Waimea Canyon, the "Grand Canyon of the Pacific," and negotiate through the bamboo forests and rainbow-draped scenery of the Na Pali Coast. The pali, or cliffs, provide a rugged grandeur of deep, narrow valleys ending abruptly at the sea. Waterfalls and swift-flowing streams continue to cut these narrow valleys while the sea carves cliffs at their mouths. Extensive stone-walled terraces can still be found on the valley bottoms where Hawaiians once lived and cultivated taro. The Kalalau Trail provides the only land access to this part of the rugged coast. The trail traverses five valleys before ending at Kalalau Beach where it is blocked by sheer, fluted pali. The 11-mile trail is graded but almost never level as it crosses above towering sea cliffs and through lush valleys. The trail drops to sea level at the beaches of Hanakapi'ai and Kalalau. Year-round.

Dogsledding the Gates of the Arctic
One of the largest and most remote wilderness areas in North America is the 8.4 million-acre Gates of the Arctic National Park and Preserve. Alaska's Brooks Range runs through the park, with two peaks, Frigid Crags and Boreal Mountains, forming the "Gates" from the central Brooks Range into the high Arctic. This adventure begins with a ski-plane flight from Bettles, Alaska, to a wilderness outpost at Eroded Mountain. Over the next nine days, you travel north through the dramatic Koyukuk River Valley. Dog teams carry all communal gear and heavy personal items while tour members take turns skiing and mushing. Camps are made in heated-wall tents along the trail. Moose, caribou, dall sheep, bears, wolves, and foxes inhabit the park. The longest day's run goes approximately 15 miles, and daytime temperatures average 20 degrees. April.

Rafting the Grand Canyon
The Colorado River through the Grand Canyon is the best single adventure trip in America, and a marvelous paradox: a wet and wooly whitewater ride in one of the most peaceful places on earth. After caroming down some of the biggest rapids on earth, such as Lava and Crystal, bask in the spectral beauty of Elves Chasm, lounge in the turquoise waters of Havasu, and wonder at the mysteries of the Anasazi ruins. The Colorado cuts a course 2 billion years and a mile deep into the Earth's crust, exposing the rainbow colors of Marble Canyon, the dark foreboding rock on the inner gorge, and side canyons of exceptional beauty. May through October.