| Description: | Montgomery County, located in central Illinois, covers an area of 704 square miles and had a 2003 population of 30,352, according to estimates by the U.S. Department of Commerce's Bureau of the Census. Using these figures, Montgomery County was the 25th largest county in Illinois geographically, but 50th largest in terms of population. Combining these two measures, Montgomery County had the 58th highest population density per square mile among Illinois 102 counties. | |