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10. Westchester County,  N.Y.

Average income: $128,127

America’s first major suburb, located north of New York City, is still the home base for many commuters to Manhattan. The biggest city within the county is Yonkers, the fourth-largest city by population in New York state. Westchester is often cited as an example of where “old money” resides. One display of that is the Gothic Revival mansion Lyndhurst, in Tarrytown. It was once owned by former owner railroad tycoon Jay Gould, who used it as his country house.

Image of Wykagyl Country Club: Getty Images