2 of richest U.S. counties are in N.J.

Forbes is out with a list of "America's Richest Counties," and two are in New Jersey.

The concentration of the others in Virginia and Maryland ought to provoke some skepticism about whether these really are America's richest areas. Here's the problem: County size varies so greatly across the country, it's no wonder some of the richest pockets fail to appear. Beverly Hills, for example, has an average household income of about $279,000, according to a Business Week list, which is more than double any county, but the glitz and glamour get averaged into all of Los Angeles County.

Gladwyne, Pa., was No. 7 on the zip code list, with Palm Beach, Fla., No 1, but their counties don't make Forbes' Top 10.

Even Philly's Center City is wealthier than the No. 10 county. Center City's average annual income is $93,222, according to "10 Richest Zip Codes in Philadelphia." But it's swallowed up as part of Philadelphia County.

Here's the Forbes County list:

1. Loudoun County, Va., median household Income: $119,525.

2. Falls Church City, Va., $117,481.

3. Los Alamos County, N.M., $110,204

4. Fairfax County, Va., $105,409.

5. Hunterdon County, N.J., $99,216

6. Howard County, Md., 99,040.

7. Arlington County, Va., $98,060.

8. Douglas County, Colo. $95,973

9. Somerset County, N.J. $95,915

10. Prince William County, Va. $93,101.

 Contact staff writer Peter Mucha at 215-854-4342 or pmucha@phillynews.com.