| Description: | Sangamon County, located in central Illinois, covers an area of 868 square miles and had a 2003 population of 191,875, according to estimates by the U.S. Department of Commerce's Bureau of the Census. Using these figures, Sangamon County was tied as the 8th largest county in Illinois geographically, but 10th largest in terms of population. Combining these two measures, Sangamon County had the 12th highest population density per square mile among Illinois 102 counties. | |