The best camping in Pennsylvania.

The Keystone State takes its nickname from its keystone role in America's founding. If you've got any interest in this time period, many historic sites can help you explore it. There are also plenty of Civil War sites for the history buff. See the site of the famous Gettysburg Address at Gettysburg National Military Park.

Adrenaline junkies of all stripes will want to check out Big Pocono State Park. Situated in the northeast corner, this park provides access to the rugged Camelback Mountain. In the winter, Camelback is a very popular skiing destination. In the summer, you can test your climbing skills—and get a rush by taking the fast way down on breathtaking zip lines.

If you're up in the northern part of the state, check out Worlds End State Park. This dramatically named area offers beautiful views of the Endless Mountains region. If you can, hit this area in spring or fall to see the colors turn. Both campgrounds and cabin rentals are available for overnight stays.

Cross-country hikers can pick up the lengthy Appalachian Trail throughout Pennsylvania. This trail runs 2,180 miles from Maine to Georgia. The A.T. bisects Pennsylvania north to south, with easy access in many small towns.