Illinois ranks first among the states in number of local governments, with 6,963 active as of June 30, 2012, according to the most recent data from the U.S. Census Bureaus's Census of Governments. This number includes 2,831 general purpose governments (counties, municipalities, and townships) and 4,132 special purpose governments (independent school districts and special districts, such as park and sanitary districts).  

To count as "governments" in the Census Bureaus' enumeration, agencies must have sufficient discretion in the management of their own affairs to distinguish them as separate from the administrative structure of any other governmental unit. In Illinois, the Department of Revenue and the Office of the Illinois Comptroller also track local governments; however, their counts differ, both from each other and from the Census Bureau, based on their different regulatory mandates.