| | Description: | Union County, located in southern Illinois, covers an area of 416 square miles and had a 2003 population of 18,170, according to estimates by the U.S. Department of Commerce's Bureau of the Census. Using these figures, Union County was the 70th largest county in Illinois geographically, but 63rd largest in terms of population. Combining these two measures, Union County had the 56th highest population density per square mile among Illinois 102 counties. | |
