"Find a County". National Association of Counties. Retrieved June 7, 2011.
sangamon.il.us
co.sangamon.il.us
"History and Overview". Springfield, Illinois: County of Sangamon, Illinois. Archived from the original on December 5, 2011. Retrieved December 4, 2011.
"History and Overview". Springfield, Illinois: County of Sangamon, Illinois. Archived from the original on December 5, 2011. Retrieved December 4, 2011.