New numbers from the US census show that the median household income for counties around the nation is $57,652, reports US News & World Report. Some counties, however, do far better than others. Witness the top five, which share a common trait: They're all around the DC area: 
 -  Loudoun County, Virginia, median household income of $129,588
-  Fairfax County, Virginia, $117,515
-  Howard County, Maryland, $115, 576
-  Falls Church City, Virginia, $114,795
-  Arlington County, Virginia, $112,138
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top 10.