| Description: | Effingham County, located in southern Illinois, covers an area of 479 square miles and had a 2003 population of 34,529, according to estimates by the U.S. Department of Commerce's Bureau of the Census. Using these figures, Effingham County was the 57th largest county in Illinois geographically, but 45th largest in terms of population. Combining these two measures, Effingham County had the 34th highest population density per square mile among Illinois 102 counties. | |