10 of the Nations 20 Richest Counties Surround Washington DC

1. Fairfax County, Va. Median income: $100,318
2. Loudoun County, Va. Median income: $99,371
3. Howard County, Md. Median income: $94,260
4. Hunterdon Country, N.J. Median income: $93,297
5. Douglas County, Colo. Median income: $92,125
6. Somerset County, N.J. Median income: $91,688
7. Morris County, N.J. Median income: $89,587
8. Montgomery County, Md. Median income: $87,624
9. Arlington County, Va. Median income: $87,350
10. Nassau County, N.Y. Median income: $85,994
11. Stafford County, Va. Median income: $85,014
12. Calvert County, Md. Median income: $84,891
13. Forsyth County, Ga. Median income: $83,682
14. Putnam County, N.Y. Median income: $81,907
15. Marin County, Calif. Median income: $81,761
16. Williamson County, Tenn. Median income: $81,449
17. Santa Clara County, Calif. Median income: $80,838
18. Prince William County, Va. Median income: $80,783
19. Alexandria City, Va. Median income: $80,449
20. Charles County, Md. Median income: $80,179
source Forbes.com