About this page This page contains a description that explains a data type in the Geographic Regions category. It provides a source for the explanation, a source for the data, a date for the data, and an explanation of the specific characteristics of the data.

Date of definition: July 2012

Counties are the primary legal divisions in Illinois.

Source of definition: U.S. Census Bureau, Geography Division. Geographic Terms and Concepts – County or Statistically Equivalent Entity

Note on number of counties and yearly changes in counties: There are 102 counties in Illinois. The number of counties has remained stable since the middle of the 19th century.

Note on data availability by county: The county is the principal geographic region for presentation of data on IECAM. All site-based data (e.g., child care), most non-site-based data (e.g., early intervention), and almost all demographic data (e.g., population) are presented by county.

List of Counties in Illinois

Counties in Illlinois