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Rich County, Poor Neighbor

The grass really is greener on the other side of the fence in some places around the country. According to a Census Bureau report, U.S. household income inequality has grown by 18 percent since 1967, although this trend has slowed in recent years.

Wealth disparity is also proving to be a hot topic during the 2012 election year, with Republican candidate Mitt Romney igniting criticism that his high net worth puts him out of touch with average Americans while the Obama administration struggles with the politically charged debate over how the country’s rich should be taxed.

Although the existence of wealth gaps is a major characteristic of the national economy, when income disparity is analyzed over smaller regions some areas show considerable drop-offs in wealth between places that sit side-by-side.

To get a sense of where these geographic income differences are the most extreme, CNBC.com analyzed Census data, using five-year estimates of average annual household income by county — the smallest granularity available — from the American Community Survey. We looked at the 200 counties with the highest average annual income and compared this metric to adjacent counties to see which had the largest relative difference in wealth. The final ranking number represents the size of this difference as a percentage of the poorer county's average annual income. This figure essentially shows the proportion that incomes in the poorer county would have to rise in order to be on par with its richer neighbor.

Counties with populations under 500 were omitted, as were counties with significant water boundaries, such as the country’s richest county, Nantucket, which has an average annual household income of $137,811.

So, where are the biggest wealth gaps in the country? Click ahead for the list.

By Paul Toscano
Posted 29 March 2012

Photo: Tony Cordoza | Photographer's Choice | Getty Images