#5 Arlington County, Virginia
Median HHI: $112,138
Population: 229,534
#4 Falls Church City, Virginia
Median HHI: $114,795
Population: 13,843
#3 Howard County, Maryland
Median HHI: $115,576
Population: 312,495
#2 Fairfax County, Virginia
Median HHI: $117,515
Population: 1.1 million
#1 Loudoun County, Virginia
Median HHI: $129,588
Population: 374,558