Illinois Route 18
|Maintained by IDOT|
|Length:||39.01 mi (62.78 km)|
|Existed:||1939 – present|
|West end:||IL 29 in Henry|
|I-39 / US 51 in Lostant|
|East end:||IL 17 in Blackstone|
|Counties:||Marshall, Putnam, LaSalle, Livingston|
Illinois Route 18 is a rural east–west state road in central Illinois. It runs east from the town of Henry at Illinois Route 29 to the town of Blackstone at Illinois Route 17. This is a distance of 39.01 miles (62.78 km).
Illinois 18 crosses the Illinois River at Henry, and is the first river crossing south of Interstate 180. The terrain is generally flat outside of the Illinois River Valley area. In Streator, Illinois 18 westbound becomes Main Street. Eastbound, it becomes Bridge Street.
From 1918 through 1927, SBI Route 18 ran from Chicago to Princeton using modern U.S. Route 34. In 1939, it was applied to what was then SBI Route 17. The next year, the route was completed and Illinois 17 moved to a new highway south of Streator.
|Stark||Henry||0.0||0.0||IL 29 (University Street)|
|Illinois River||1.2||1.9||Henry Bridge|
|Marshall||||2.1||3.4||IL 26 south||West end of IL 26 overlap|
|Putnam||||2.8||4.5||IL 26 north||East end of IL 26 overlap|
|La Salle||||16.5||26.6||I-39 / US 51 – Bloomington-Normal, Rockford|
|Streator||29.1||46.8||IL 23 (Bloomington Street, Park Street)|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi