Washington & Old Dominion (W&OD) Railroad Regional Park
 
Often called the skinniest park in Virginia, Washington & Old Dominion (W&OD) Railroad Regional Park is a paved trail between Shirlington and Purcellville, Virginia. Run, cycle or skate the 45-mile route along the former roadbed of the Washington & Old Dominion Railroad, which runs through the urban heartland and into the Virginia countryside. Equestrians can ride the adjacent 32-mile gravel horse trail. 
 
The W&OD trail has multiple parking areas, enabling you to jump on and off the trail at various points. Excerpted from the NOVA Parks, Washington and Old Dominion Railroad Regional Park site