The number of unemployed residents in the county increased from 2,708 people in November to 2,746 people in December, according to the Labor Department.
The number of employed residents in the county decreased by 1,370 people to 66,854 workers in December.
The civilian labor force decreased by 1,332 people to 69,600 people in December.
In December, Berwick Offray Vice President of Human Resources Nancy Schott announced the Hagerstown plant would lay off 25 employees by the end of February.
TruServ was still gradually laying off workers at the distribution center on Hunters Green Parkway as the company prepares to close the center by March 31. The center had 16 employees in January.
Wolf said she doubted those layoffs were enough to raise the unemployment rate to 3.9 percent.
The Mack Trucks powertrain plant north of Hagerstown had a winter/holiday shutdown toward the end of December, but not the week the survey was taken. The employment survey is conducted the week of the 12th.
The Berwick Offray ribbon manufacturing plant also shut down for Christmas week, according to the Labor Department.
Frederick County's unemployment rate remained steady at 2.4 percent in December, according to the Labor Department.
Montgomery County had the lowest unemployment rate in the state in December at 2.2 percent. The highest unemployment rate was 11.7 percent in Worcester County on the Lower Eastern Shore.
Maryland's jobless rate decreased from 4 percent in November to 3.8 percent in December.
The national unemployment rate remained steady at 5.7 percent in December.