I can't find the original source, but a bunch of travel blogs all parroted the same information last October so presumably it came from a press release that was distributed to all of them. According to these blog posts:
Originally Posted by
chrisny2
I noticed this in the former Sam & Harry's Space near the entrance to the D gates at DCA. If it's just that former restaurant space, it's pretty tiny.
DCA will be 5,483 square feet.
Originally Posted by
Hoi polloi
Sorry if I missed it, but have they announced where the LGA C1 lounge will be?
In the pedestrian bridge leading to the western concourse of the new Terminal B, with a dual indoor/outdoor space.