Numbering and direction follow [[Road names/USA|USA road naming]] guidance. When county highways contain a letter, the format is '''CH-XNN'''. For example, '''CH-W25'''.
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/USA| 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 [http://www. idot. illinois. gov/transportation-system/Network-Overview/highway-system/maps IDOT Maps. ]
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 ==