In 2013, D.C., Maryland, and Virginia also all landed in the top 10, with Maryland topping the list. (In 2013, 7.7 percent of Maryland’s households were millionaires, compared with 7.67 percent in 2014.)
The rankings aren’t all that surprising. Census data in 2011 found that seven of the nation’s richest counties were located in the Washington region, with Loudoun and Fairfax ranking first and second, respectively. Maryland had the nation’s highest household income, and Virginia was ninth.
The wealth in this highly educated region is indicative of an economy supported by the federal government and its contractors, which allowed the area to weather the recession better than most in the country.