The United States, with its varied topography, is a nature-lover's dream. Whether it's a scenic alpine amble or a tough desert hike, the following trails have it all.

Appalachian Trail

This famous route stretches across 2,159 miles of Appalachian Mountain ridgelines from Maine to Georgia. You'll find great bird and wildflower viewing and, in the fall, brilliant foliage, especially in Vermont's Green Mountains. (Appalachian Trail Association: 304-535-6331)

Continental Divide

You can't get more stunning mountain backdrops than from this 3,100-mile route that travels the length of the Rocky Mountains from Mexico to Canada. The trail encompasses five states—Montana, Idaho, Wyoming, Colorado and New Mexico. (Continental Divide Trail Alliance: 303-838-3760)

Pacific Crest Trail

This rugged trail follows the crest of the Sierra Nevada and Cascade mountain ranges and covers some 2,638 miles from Mexico to Canada. Route highlights: the Sonoran Desert, Sequoia National Forest and Glacier National Park. (Pacific Crest Trail Association: 916-349-2109)

Northville-Placid Trail

This 133-mile trail in northern New York takes in the southern Adirondack foothills and the picturesque High Peaks region. This trail is known for its abundance of freshwater lakes including Lake Saranac and Lake Placid. (Adirondack Mountain Club: 518-668-4447)

Tahoe Rim Trail

This recently completed hiking and equestrian path (with elevations up to 9,400 feet) follows a 150-mile loop around Lake Tahoe in the Sierra Nevada of California and Nevada and affords spectacular mountain and lake views. (Tahoe Rim Trail Association: 775-588-0686