Roads of the Mid-South & West > Highways of the State of Illinois > Illinois I.D. Routes
Illinois State I.D. Routes
In Illinois, the state maintaines highways that are not on maps. They show a number in the 900 and 8000 number range. The only place these are posted are on the state mile marker.
Illinois mile markers are used by most counties. These signs are white squares. Centered in the square is a green circle. Across the center of the circle is a green bar. The name of the county is in the green bar. To the top of the bar is the highway number. Below the bar is the mile number from the origin of the highway in that county, or from the county line.
So far RMS&W has came across 29 of these such I.D. highways.
In a e-mail sent to the Illinois Department of Transportation, Rob Robinson, Data Management Unit Chief, stated that District Four Inventory Staff does confirm these mile markers with the 900 number on then in the location in Tazewell County. The reply went on to say that they (IDOT) are un-clear on what these 900 highway numbers represent. There are no highways in the 900 range on the states route log.
7 January 2012