| Description: | Fayette County, located in southern Illinois, covers an area of 717 square miles and had a 2003 population of 21,539, according to estimates by the U.S. Department of Commerce's Bureau of the Census. Using these figures, Fayette County was the 21st largest county in Illinois geographically, but 57th largest in terms of population. Combining these two measures, Fayette County had the 20th smallest population density per square mile among Illinois 102 counties. | |