ATLANTA — The Georgia Department of Labor announced Thursday that the preliminary unemployment rate in metro Savannah rose to 8.2 percent in December, up five-tenths of a percentage point from 7.7 percent in November. The rate was 8.7 percent in December 2011.

The preliminary unemployment rate in the Coastal Georgia region rose to 8.7 percent in December, up five-tenths of a percentage point from 8.2 percent in November. The rate was 9.2 percent in December 2011.

Unemployment in Effingham County stood at 7.4 percent for December 2012, up from 7.1 percent for November 2012. Effingham’s unemployment rate for December 2011 was 7.7 percent.

The rate rose because of a combination of factors — a slight increase in initial claims for unemployment insurance benefits and an increase in the labor force, as more people began searching for work.

There were 39 more new claims for unemployment benefits in construction, manufacturing, trade, transportation and warehousing, and accommodations and food services. While the initial claims were up from November to December, they were down by 1,024, or 41.6 percent, from 2,460 in December 2011. The decline in claims led to an over-the-year drop in the area’s jobless rate.

The labor force, those employed or actively searching for a job, increased by 1,411, rising from 179,537 to 180,948 in December. The new jobseekers are counted as unemployed until they get work.

Metro Athens had the lowest area jobless rate at 6.6 percent, while the Heart of Georgia-Altamaha region had the highest at 11.4 percent.

Meanwhile, Georgia’s seasonally adjusted unemployment rate increased to 8.6 percent in December, up one-tenth of a percentage point from 8.5 percent in November. The rate was 9.4 percent in December a year ago.