Effingham County is a county located in the U.S. state of Georgia. As of the 2010 census, the population was 52,250. The seat is Springfield.Effingham County is included in the Savannah, GA Metropolitan Statistical Area.In 2008, Effingham County was ranked as the sixth fastest-growing midsize county in the nation from 2000 to 2007 by the U.S. Census Bureau. The county had a 35.1% growth rate over that period.