Illinois Route 111
|Maintained by IDOT|
|Length:||82.18 mi (132.26 km)|
|Existed:||1924 – present|
|South end:||Lake Drive in Centreville|
| I-64 in Washington Park
US 40 / I-55 / I-70 in Collinsville
I-270 in Pontoon Beach
IL 3 / US 67 in Alton
US 67 / IL 267 in Godfrey
|North end:||IL 104 in Waverly|
|Counties:||St. Clair, Madison, Jersey, Macoupin, Morgan|
Illinois Route 111 is a north–south state road in southwestern Illinois. It runs from Short Street (near Lake Drive and 1/4 mi NW of Interstate 255) in Centreville to Illinois Route 104 in Waverly. This is a distance of 82.18 miles (132.26 km).
In August 1960 a new alignment in Alton on what is now the Homer M. Adams Parkway opened to traffic from Route 100 to Route 140. A second new alignment, Bellwood Road Extension in Bethalto, opened a few years later that would link Route 111 up with Vaughn and Central in Wood River. The original alignment of IL 111 in Alton had it cut up Sixth Street in Wood River, Old Alton-Edwardsville Road (with an overlap with then-IL 159), and up Broadway in Alton until its overlap with US 67 using Belle Street.
SBI Route 111 originally ran from Waverly to Alton on modern-day Illinois 111. In 1942, it was extended south to Fairmont City. In 1953, it was extended further south to near East Saint Louis, which became Centreville. In 2001, when U.S. Route 67 was moved west through Jerseyville, Illinois Route 267 took its place north of Medora. Some time after, Illinois 267 was applied south along with Illinois 111 on a concurrency.