Prince William Forest Park Visitor Center
Address: 18170 Park Entrance Road, Triangle, VA 22172
Built in the Depression as Chopawamsic, where city children came to camp in the woods, this 13,000-acre forest near Washington then trained OSS spies for World War II in its secluded cabin camps; today it is the region's largest protected Piedmont forest, laced with 37 miles of trails.
Wade Quantico Creek, stay in the historic cabin camps, and walk the forest trails; young kids can earn a Junior Ranger badge. For a challenge, hike or bike the full fire-road and singletrack network through the deep forest.
Coordinates: 38.55991, -77.34714