41. Lincoln County, South Dakota
> County median household income: $74,751
> State median household income: $49,495
> Pct. households in county making $200,000 or more: 5.6%
> 2013 county unemployment rate: 2.9%

In addition to high incomes, Lincoln County residents also benefited from a strong job market and good health coverage. Less than 3% of the area’s workforce was unemployed in 2013, and 5% of residents did not have health insurance during the five years through 2013. Both were among the lowest rates nationwide. Also, just 4.5% of residents lived in poverty over that period, less than a third of the comparable national rate.

42. Williamson County, Tennessee
> County median household income: $89,779
> State median household income: $44,298
> Pct. households in county making $200,000 or more: 14.0%
> 2013 county unemployment rate: 5.6%

Tennessee is among the nation’s poorest states. Due to exceptionally uneven income distribution, however, residents of Williamson County were both the richest state residents as well as some of the wealthiest in the nation. A typical household in the county earned nearly $90,000 annually over the five years through 2013, $62,965 more than the comparable income in Grundy County, the state’s poorest area. County residents were extremely well educated — nearly 53% had at least a bachelor’s degree on average over that period, considerably higher than the national rate and among the nation’s highest.

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43. Rockwall County, Texas
> County median household income: $86,119
> State median household income: $51,900
> Pct. households in county making $200,000 or more: 7.7%
> 2013 county unemployment rate: 5.8%

As in other states’ wealthiest counties, high incomes in Rockwall County made it easier for residents to own their homes. Nearly 84% of area housing units were owned by their occupants between 2009 and 2013, considerably higher than the comparable national figure and even higher than most other wealthy counties reviewed. Rockwall incomes also reveal a relatively large income gap among Texas residents. The county had a median annual household income of more than $86,000, versus less than $25,000 in Starr, the state’s poorest county.

44. Summit County, Utah
> County median household income: $83,336
> State median household income: $58,821
> Pct. households in county making $200,000 or more: 14.4%
> 2013 county unemployment rate: 3.9%

Nearly 48% of adults in Summit County had at least a bachelor’s degree during the five years through 2013, one of the highest rates nationwide. The high educational attainment rate likely helped area residents earn the highest incomes in the state. A typical Summit County household earned $83,336 annually between 2009 and 2013, one of the highest figures in the nation.

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45. Chittenden County, Vermont
> County median household income: $63,989
> State median household income: $54,267
> Pct. households in county making $200,000 or more: 5.5%
> 2013 county unemployment rate: 3.5%

Chittenden County residents were able to access the larger and higher-paying job market in Burlington, Vermont’s largest city, which is located in the area. Partly as a result, Chittenden’s unemployment rate was just 3.5% in 2013, one of the lowest in the country. A typical household in Chittenden earned nearly $64,000 annually during the five years through 2013, the highest in the state, and just over $22,000 higher than the comparable figure in Orleans, Vermont’s poorest area. This was one of the smaller such income gaps reviewed.