IECAM uses the term
township to refer to all three of these types of county subdivisions. In Illinois, most counties are divided into townships. However, 17 counties, mostly in the southern part of the state, are divided into precincts. Source of definition: U.S. Census Bureau, Geography Division.
Geographic Terms and Concepts – County Subdivision
County subdivisions periodically change (more so in counties that use precincts) as old subdivisions are combined or divided, as new subdivisions are created, and as county subdivisions undergo boundary changes. Therefore,
- the number of townships (or other county subdivisions) may change from year to year,
- township X in one year may not cover the same geographic area as township X the following year, and
- a township or precinct may not have the same name from one year to the next.