Bryce Canyon National Park, UT
Just beyond Bryce Canyon National Park's well-traveled Rim Trail, which overlooks its famed amphitheater-shaped canyon, awaits the park's seldom-traveled backcountry. Ambitious backpackers should target the 22.9-mile Below the Rim Trail, which takes you to pristine arid forestland, red-rock peaks, and refreshingly isolated backcountry campgrounds. Go early in the month to catch the end of fall color and beat possible snow showers.

Shenandoah National Park, VA
With two of Virginia's premier leaf-peeping drives, it's no wonder Shenandoah National Park takes the autumnal crown. Skyline Drive snakes through the entire park and links up with the Blue Ridge Parkway (the southern Appalachian granddaddy of byways). Most of Shenandoah's hiking trailheads start on Skyline Drive, with the exception of the ever-popular Old Rag Mountain. A word of advice: If you plan to hit Shenandoah on its peak fall weekend (the third week of October), get there the night before and beat the hiking crew commuting in from metro D.C. The road leading to Skyline Drive can resemble a parking lot in late October.

Acadia National Park, ME
More than 120 miles of hiking trails, two campgrounds, and 45 miles of biking on carriage trails are just some of the attractions in Acadia National Park. Learn how glaciers carved Acadia’s landscape and what plants and trees are found along trails by attending a ranger-led tour. During the winter months, activities such as cross-country skiing, snowmobiling, and hiking are available; however, the best time to visit Acadia is late summer or fall.

Land Between the Lakes National Recreation Area, TN & KY
Make your next trip an adventurous one by visiting Kentucky and Tennessee’s Land Between the Lakes National Recreation Area. Fun can be found for all ages with the 700-acre Elk and Bison Prairie, the Golden Pond Planetarium, more than 200 miles of hiking trails, and various hands-on nature programs. You can also step back in time to the 1800s and experience a living history farm at the Homeplace; you'll be just in time to catch the fall harvest.

Arches National Park, UT
Arches National Park contains the highest density of natural arches in the world, some 2,000, sculpted by millions of years of wind, rain, erosion, and other forces of geology and time. You can drive on a paved road past many of the popular natural features, combining short hikes with a road tour. The park has dozens of hiking trails for all abilities, and the fall's cooler temperatures mean you'll enjoy the trails even more.

Black Canyon of the Gunnison National Park, CO
Compared to the Colorado antediluvians Rocky Mountain and Mesa Verde, relative newcomer Black Canyon of the Gunnison remains quiet, and even the landscape looks startlingly fresh. Although the gorge was formed 30 million years ago, it is strikingly narrow and steep compared to other well-worn canyons. October brings pleasant weather to the canyon, but be aware that weather can vary greatly between the canyon rim and floor. The hikes along the rim offer more than a little vertigo, and the Gunnison River below foams with Class V whitewater—prime for the expert kayaker.

Dry Tortugas National Park, FL
Just when you're mourning summer's end, Florida's Dry Tortugas National Park still offers those mild temps we begin to long for as the cooler weather takes root. The 80-degree waters are perfect for scuba divers and snorkelers, and the pelicans are still nesting in the fall. But make sure you check the weather before heading south—every month except April and May is fairly unpredictable.

Zion National Park, UT
Utah's Zion National Park is almost as trammeled as the Great Smokies in terms of yearly visitation. But the advantage of Zion is that its famous rock formations don't change from season to season, and the dry climate remains throughout the year—ample justification for its status as a perennial favorite. While the visitor numbers tell a tale of spring popularity, fall is a worthy alternative to shake the crowds—and the autumn colors certainly compete with the snowmelt waterfalls of spring.

New River Gorge National Recreation Area, WV
On the third weekend of October, the 867-foot New River Gorge Bridge hosts its annual Bridge Day Festival, where BASE jumpers leap off and drop to the churning New River far below. The festival also coincides with the final weekend of the Gauley River rafting season, which becomes one of the world's most furious rivers when water is released from the Summersville Dam from September through October.

Chattahoochee-Oconee National Forests, GA
These two forests are close neighbors with very different characteristics. The Chattahoochee is the more rugged of the two and includes a piece of the legendary Blue Ridge Mountains. Often called a hiker's paradise, the Chat has more than 430 miles of trails that wander through mountains, wind along rolling hills, and traverse wild rivers. The Oconee stretches across the gently rolling Piedmont section of central Georgia. This is a family fishing and camping paradise, centered around Sinclair Lake. Fall color is spectacular in the forests, particularly along the Russell-Brasstown National Scenic Byway and the Ridge and Valley Scenic Byway.