Housing in the U.S., except for a few regions, is still relatively cheap. And, unlike stocks, there is a strong reason for sustained demand: record high immigration. New immigrants (many illegal, but until I see evidence of anything being done about that, they are in the demand pool) are sleeping 5 to a room in NYC. They will move into apartments and, eventually, houses.
Until we get reliable numbers on immigrants, it is impossible to call a housing bubble. All the anecdotal evidence I have indicates to me that the entire populations of Russia and Brasil have moved the the U.S., nevermind that Mexico has colonized California.
Regarding DC and Baltimore: I live in the DC-Baltimore region (Ellicott City, MD) and while prices have been crazy, the Federal Government provides a job market that doesn’t exist anywhere else.