America's a big country, but that doesn't mean you can't see it on foot. Decades ago, conservationists protected chunks of wilderness to be designated as hiking trails, and those routes are still there — some of them offering miles of serene wilderness, others with chunks of nature broken up by roads and development.

The greatest of them all? There are two, one on each coast: The Appalachian National Scenic Trail, completed in 1937, which stretches 2,175 miles between Maine and Georgia; and the Pacific Crest Trail, which runs 2,650 miles between Mexico and Canada, passing through California, Oregon and Washington.

The Appalachian Trail Conservancy maintains a Web site at www.appalachiantrail.org, with history, maps, trail conditions, volunteer opportunities, descriptions of flora and fauna, and just about everything else you need to find out before you pull on your hiking boots for a months-long 14-state wilderness experience.

The Web site for the Pacific Crest Trail Association, at www.pcta.org, also offers some history, an events calendar, and, like the Appalachian Trail site, places where hikers can log photos and journal entries. There the hikers thank their families, their friends, God, and others for the chance to take a break from regular life to tackle the glacier-capped peaks of the West Coast wilderness.

Still under construction is the Continental Divide National Scenic Trail, a planned 3,100-mile backcountry route between Mexico and Canada through the Rocky Mountains. The trail passes through Montana, Idaho, Wyoming, Colorado, and New Mexico, including Glacier National Park and Yellowstone National Park. At the site of the Continental Divide Trail Alliance, www.cdtrail.org, you can find trail-building projects where volunteers put the pieces of the trail together. About 70 percent of the trail is useable now.

Most people just tackle pieces of these long trails, of course. For maps to those shorter hikes and thousands of others around the United States, try the subscription service gorp.away.com. Click on "Where to Hike" and you'll see a map of the United States; choose a state to find an array of options.

The American Hiking Society site, www.americanhiking.org, will steer you to a hiking association in your part of the country, and it has plenty of listings for volunteer trail work.

If you would like your canine to be in on all this, check out www.hikewithyourdog.com, which lists some of the outdoor parks and monuments where dogs are welcome in the United States and Canada.

Need someone to hike with? Check out hiking.meetup.com. It's got a hiking group for just about everyone, somewhere.