| Description: | Lee County, located in northern Illinois, covers an area of 725 square miles and had a 2003 population of 35,537, according to estimates by the U.S. Department of Commerce's Bureau of the Census. Using these figures, Lee County was the 19th largest county in Illinois geographically, but 42nd largest in terms of population. Combining these two measures, Lee County had the 51st highest population density per square mile among Illinois 102 counties. | |