| Description: | Hamilton County, located in southern Illinois, covers an area of 435 square miles and had a 2003 population of 8,334, according to estimates by the U.S. Department of Commerce's Bureau of the Census. Using these figures, Hamilton County was the 66th largest county in Illinois geographically, but 13th smallest in terms of population. Combining these two measures, Hamilton County had the 3rd lowest population density per square mile among Illinois 102 counties. | |