James
Google
A wonderful escape from the bustle of the city, this reclaimed island in the middle of the Potomac River is where one can find the Teddy Roosevelt Memorial and a few miles of trails in different ecosystems (marsh, swamp, and upland forest).
While it is picturesque and lots of trails, it is more of a walk than a hike. Given its proximity to the airport, one can hear the loud noises of planes flying overhead, which ruin the natural environment slightly. In addition, there is only one way on/off the island, a pedestrian bridge that is difficult to access through means of public transit (20 minute walk from Rosslyn metro station or walk across Francis Scott Key bridge from Georgetown).
Generally a great place to visit, but not necessary if one is short on time.