These counties have the fastest wage growth

Wage growth -- or the lack of it -- has been weighing on American workers, given that pay stagnation has become a very real issue for the middle class. Yet in some pockets of the country, wages are growing at a fast clip.

Many counties where workers are seeing pay climb at twice the national rate or more are, no surprise, home to large, fast-growing cities or wealthy suburbs where skilled, educated workers are breaking ahead of the pack. That trend has increasingly characterized the post-recovery years: Some regions of the country are reaping the benefits of the expanding economy, while others fail to capture any gains.

The top-performing region is Rockland County, New York, a suburb of New York City whose cities include Nyack and Suffern and where the median home price is $388,600, according to Zillow. Workers there saw weekly wages jump by almost 25 percent in third-quarter 2015, compared with the nation's average wage growth of 2.6 percent, according to the Bureau of Labor Statistics. The biggest contribution to the wage gains in Rockland County came from manufacturing, a segment that historically has buoyed the middle class but has been muted by automation and outsourcing.

While that corner of the country is pulling ahead, many Americans aren't feeling the largesse. Wage inequality has gotten worse since the 1970s, according to Economic Policy Institute's Elise Gould, who wrote in a research note on Thursday that the latest data for wage growth in 2015 illustrates that those trends are continuing.

Wage growth for the highest-paid workers -- those in the 95th percentile --rose 6.4 percent last year to $56.60 an hour, while those in the 50th percentile saw pay rise just 1.7 percent to $17.21 an hour. Interestingly, the lowest-paid workers saw wages rise 3.3 percent to $8.92 an hour, reflecting a higher percentage gain than many in the middle class, which is likely due to higher minimum-wage laws and raises at low-wage employers such as Walmart (WMT).

"Those with the highest wages have had the fastest wage growth in recent years," Gould wrote. "This trend continued quite clearly between 2014 and 2015."

Income inequality is leaving its fingerprints across the country, creating "geographical segregation" between the haves and the have-nots, according to 2012 research from the Federal Reserve Bank of Boston. Wealthy families are isolating themselves from the poor, while poor communities may enter a "downward spiral" if they're unable to attract middle-class residents, the researchers noted.

So, which counties experienced the greatest wage gains? After Rockland, the county with the second-biggest weekly wage gains is Lake County, Illinois, home to wealthy Chicago suburbs such as Highland Park and Lake Forest. Wages there rose by 11.7 percent in the third quarter, the BLS said. (A full list of counties with the largest wage gains follows below.)

Meanwhile, 20 counties experienced wage decreases, with the worst performer being Midland, Texas, in the heart of the country's energy sector. The decline there averaged 6.7 percent, which relates to the fall in oil prices and regional employment.

These are the top 10 counties with above-average wage growth.

1. Rockland, New York -- 24.9%

2. Lake, Illinois -- 11.7%

3. Onondaga, New York -- 6.5%

4. Washington, Oregon -- 6.4%

5. Marin, California -- 6.1%

6. Santa Cruz, California -- 6.1%

7. Genesee, Michigan -- 5.6%

8. Davidson, Tennessee -- 5.5%

9. Placer, California -- 5.4%

10. Williamson, Tennessee -- 5.2%