Arlington It's Both Arlington Loop
Distance: 17-mile loop.
Riders can do a fun loop of Arlington County by connecting four trails—the Custis Trail from Rosslyn to Bon Air Park (where you can take a break in the fragrant rose garden); the W&OD Trail from there to Shirlington (where you can get a bite to eat or watch dogs splashing in the nearby dog park); then Four Mile Run to the Mount Vernon Trail to complete the circuit. The trail is narrow in spots; once you're on Mount Vernon, it can be particularly busy near Reagan National Airport, but it's worth stopping at Gravelly Point to watch airplanes coming and going right over your head. If you're really fortunate, you may spot a heron where Four Mile Run meets the Potomac. For a map, see bikearlington.com.