From the "deservedly obscure" department, in case anyone else cares (or even climbed it already, not that I saw any evidence anyone tried anytime recently) --
There's just one outcrop along the Potomac at Turkey Run Park that isn't short, and just one obvious line on it, maybe with a couple variations, but at least it's close to the parking lot and the Beltway. The route (on the face out towards the water, not the blankish side face in the photo) is 35-40' and has two overhangs and a nice-looking finger crack on top, maybe 5.11. Looks like good pro from cams under one inch.
Turkey Run Park is a couple miles downstream of Boucher Rocks -- head east on George Washington Parkway from 495, take the first exit (sign for Turkey Run Park) and then the first parking lot (C1), walk about 100 yards down the path to the river until you reach a tree with a yellow blaze on the right, turn right off the trail, and trend left instead of going down anything steep (don't climb down any rocks) to reach the level platform on the hillside (visible in the picture) that is the top of the climb, and either rig your anchor to the trees and rap off or scramble down the mud/dirt on the side. The top is maybe 50 yards off the trail, but you don't see it until you're a dozen yards away. The outcrop is easier to see from below -- after you reach the river and turn right onto the riverside trail, within 100 yards you should see an outcrop that looks possibly climbable. Head up to that
-- it's probably the wrong outcrop, but the right one is twenty yards away.
The outcrops mostly have bad bouldering landings. Don't bother.