To continue my prompt to study the map for more short sections of
highways that dip into Virigina, see also the section at Graveley
Point (southern end of the map) where there is an inlet to a bird
sanctuary - it's unclear how far the District shoreline extends into
the channel leading to the santuary lake, but part of this road might
well be in DC at this point, too.

Also, a little north of Gravelyu Point just south of Ladfy Bird
Johnson park, there are loops on Hwy 395 forming access ramps that are
on "added land that weren't there when the border was named to be
along the shore - this part was added and the added part didn't cause
the border to change - it is still Virginia.

Lastly, a technical correction, the overpass I mentioned in my last
message west of Roosevelt Island is not part of 66, but part of the
George Washington Memorial Parkway that parallels 66 at this point.
The parkway is an unnumbered federal highway under the jurisdiction of
the Park Service. It starts on the northern section of the beltway
the encircles the District of Columbia, and parallels the Potomac
River, ending at Washington's home at Mt. Vernon, about 10 miles south
of the District.

LN