Butler County’s estimated unemployment rate rose slightly in September, new figures show, but the county maintained the lowest rate of the seven counties in Pittsburgh’s metropolitan statistical area.

The unemployment rate in Butler County rose from 3.6 percent to 3.8 percent in September. The rate is down from 5.2 percent the previous year, according to Pennsylvania’s Department of Labor and Industry’s Center for Workforce Information and Analysis.

The state’s unemployment rate remained at 4.1 percent while the nation’s rate fell to 3.7 from 3.9 percent, according to the center’s new report. Allegheny County’s rate rose from 3.8 to 4 percent.

Butler County’s labor force grew from 97,300 to 98,200 in September, the report shows, while raw unemployment also grew from 3,500 to 3,800.

The total number of employed people in Pittsburgh’s seven county area grew to 1,193,500 from 1,182,100. The center considers Allegheny, Armstrong, Butler, Beaver, Fayette, Washington and Westmoreland counties as the Pittsburgh metropolitan area.