New York’s Adirondaks are still rebounding after 10,000 years.
True, so is a lot of the north, wherever the ice sheets were sufficiently thick. 10,000 years is a short time in geology. I don’t know whether or how the D.C. subsidence would be coupled to that. As I said, I don’t know enough about the tectonics of the Eastern Seaboard to draw conclusions either way, just that the article writer got the whole depression/rebound thing wrong.