With their proximity to Wall Street, it’s no surprise, really, that Nassau and Suffolk County have made Forbes’ list of America’s 25 richest counties.

Based on U.S. Census data from nearly 2000 counties for 2008, Nassau, with a median household income of $93,579, hit No. 11, and Suffolk (median household income of $84,767) trailed the pack at No. 25.

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Forbes noted that some of the counties on the list from the tri-state area might get bumped down or knocked out next year when the next American Community Survey is released later this year. That date will reflect incomes for 2009, after the Wall Street implosion.

And while Long Island may be one of the wealthiest regions in the country, it’s also one of the most expensive. A new study by the Center for Neighborhood Technology found that more areas of Long Island become "unaffordable" when you figure in the cost of transportation.