New Census Bureau data shows nearly half of the nation's 20 wealthiest counties, based on median household income, are in the Washington region.
Five of the top 10 are in Northern Virginia.
The data, from the Census Bureau's Small Area Income and Poverty Estimates program, ranks Falls Church City at the top of the list, with a median household income of $121,500 in 2012. It was deemed a county equivalent because it is an independent city.
Loudoun County ranks No. 2 in the nation, at $118,934. Howard County, Md. is fourth, Fairfax County is fifth, Arlington County is seventh and Stafford County, Va. is ninth.
"Metropolitan counties along the East Coast continued to have the highest median household income and lowest poverty in the country," said Lucinda Dalzell, chief of the Census Bureau's Small Areas Estimates Branch.
"These counties are located in large metro areas, such as Boston and New York, and are heavily concentrated in the Northern Virginia portion of the Washington area."
Northern Virginia alone accounts for about one-fifth of the nation's 50 highest-income counties.
Last month, Commerce Department data ranked the Washington metro fourth in the nation for per capita income.
Here are the top 20 counties for median household incomes in 2012, according to the Census Bureau:
- Falls Church City, Va. $121,500
- Loudoun County, Va. $118,934
- Los Alamos County, NM $112,115
- Howard County, Md. $108,234
- Fairfax County, Va. $106,690
- Hunterdon County, NJ $103,301
- Arlington County, Va. $ 99,256
- Douglas County, Colo. $ 98,426
- Stafford County, Va. $ 95,927
- Somerset County, NJ $ 95,574
- Morris County, NJ $ 95,236
- Montgomery County, Md. $ 94,365
- Pr. William County, Va. $ 93,011
- Williamson County, Tenn. $ 93,003
- Putnam County, NY $ 92,950
- Nassau County, NY $ 92,543
- Santa Clara County, Calif. $ 91,195
- Charles County, Md. $ 89,203
- Marin County, Calif. $ 88,654
- Hamilton County, In. $ 88,429
© 2013 American City Business Journals, Inc.