Butler County’s unemployment rate has fallen below 6 percent for the first time in nearly five years.

The rate was 5.4 percent in December, making it the lowest rate in the nine counties in southwestern Pennsylvania.

Allegheny County, which had a rate of 5.6 percent, was the only other county below 6 percent.

The rate in Butler County fell from 6 percent in November. The last time the rate was below that mark was January 2009, when it was 5.8 percent.

Dave Culp, chairman of the School of Business at Slippery Rock University, said the mark is evidence of an improving economy in the county.

“We consider full employment to be around 5.5 percent,” he said. “So 5.4 percent is pretty good.”

John Pileggi, the program supervisor at CareerLink in Butler County, called the 5.4 percent rate encouraging for the county.

“I was pleasantly surprised to see it,” he said. “Hopefully it will continue to drop.

CareerLink is a nonprofit agency that provides services for employers and job seekers.

The statewide unemployment rate for the month was 6.9 percent, slightly above the national rate of 6.7 percent. Both the state and national rates dropped in December.

It was announced Friday that the national jobless rate for January hit 6.6 percent.

Pileggi said the widespread reduction in unemployment makes him more confident that the drop was not simply an anomaly.

“If we just saw the drop here, I think I’d be a little more skeptical,” he said.

Culp attributed the holiday season to having an impact on the reduced rates.

“Things usually pick up before Christmas,” he said, adding that Butler County has a lot of service jobs that would have benefited from the season.

Culp said the 5.4 percent mark shows the economy is doing well in the county.

“The economy is past its critical point,” he said. “I’m very optimistic about the numbers. I have a couple kids working in Butler County, and I’m becoming much more comfortable that they will stay employed in the future.”

Culp said unemployment rates are one of the key statistics used in determining the strength of an economy.

“No measure is a perfect measure, but it’s a good gauge of how the economy’s doing,” he said.

Each of the nine counties in the region had significant drops in their unemployment rates in December, but some were still more than a full percentage point above Butler County.

Mercer and Armstrong counties had 7.2 percent and 7 percent rates, respectively.

“I think Butler County benefits from people that work in Allegheny County but don’t want to live there,” Culp said.

Pileggi said Butler County typically has lower unemployment rates than most of its neighbors.

“Butler County has a strong business population,” he said, adding that years of planning has enticed numerous businesses to call it home.

Pileggi cited Cranberry Township’s Thorn Hill Industrial Park as an example of the county’s economic success.

Culp said the strong figures also may inspire more people who are not seeking employment to start searching for jobs again.

“Usually as the unemployment rate goes down, discouraged workers get back into the labor force,” he said.