User:Hawkeygoal/IL Pages/IL Highway Numbering (2016 06) History

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Revision as of 01:37, 21 June 2016 by Hawkeygoal (talk | contribs) (punctuation fix)


The goal of this page update is to revise the US, State, and County Route Naming portion of the Major roads section of the Illinois wiki.

This information is under consideration for the Illinois state wiki.
It should not be considered official guidance.

Illinois counties maintain a system of routes or highways within their borders. A separate coordinate-based system for rural county roads also maintained. At present, both are prefixed "CR-." The principal change in this update is to alter that guidance.

The current wiki guidance on this topic can be found in this section.


Road naming

In Illinois, USA road naming guidance is followed with the following local exceptions:

  • State Routes or Highways are named with SR-XXX.
  • County Routes or Highways are named CH-XXX.
  • County Roads are named CR-XXX.
  • Township Roads are named TR-XXX.

Numbering and direction follow USA road naming guidance. When county highways contain a letter, the format is CH-XNN. For example, CH-W25.

County routes or highways may or may not be shielded. These roads nearly always carry a local primary street name. CH- designations apply to alternate names almost exclusively. The designation is used to identify county routes for proper application of road types.

Proper sourcing of county routes and highways is important. The interactive IDOT functional classification map uses a third-party base map source which may not be correct. In order of preference, source county route/highway numbering from WME SV images less than three years old, published county information, or the IDOT county highway maps available at | IDOT Maps.

The naming of county highways was changed in July 2016. Previously, county routes were also labeled "CR-" and should be updated to the new guidance. Care must be taken to not change the naming of county/township roads which are currently named using "CR-." See the state to-do list for counties outstanding.

Additional Changes

This will require additional updates to the USA Highway naming page to reflect amended guidance.


This proposal is under discussion on the forums, at the following link: