Prince William National Forest Park, Triangle

Established in 1936 and spanning over 17,000 acres along the Quantico watershed, this national park is the largest protected natural area in the Washington, D.C., metropolitan region and it includes a variety of amenities including 37 miles of hiking trails, 21 miles of bicycle accessible roads and trails, several tent camping options, rustic cabin camping, and a full service, concessionaire-operated RV campground.