Spanning 45 miles between Shirlington and Purcellville, the Washington & Old Dominion Railroad Regional Trail (W&OD) offers runners, cyclists, and skaters a serene and historic path through nature. The W&OD Trail is a long, narrow park that winds along the former roadbed of the Washington & Old Dominion Railroad, through the heart of Vienna and, on either end, to the edge of Washington, DC and into the Virginia countryside.