Illinois Route 111 (IL 111) is an 82.18-mile-long (132.26 km) north–south state highway in the southwestern part of the U.S. state of Illinois. It travels from Short Street (near Lake Drive and 1⁄4 mile (0.40 km) northwest of Interstate 255) in Centreville to IL 104 in Waverly.

IL 111 has concurrencies with IL 3 in Alton, U.S. Route 67 (US 67) in Godfrey, and IL 267 from Godfrey to Medora.

In August 1960, a new alignment in Alton on what is now the Homer M. Adams Parkway opened to traffic from IL 100 to IL 140. A second new alignment, Bellwood Road Extension in Bethalto, opened a few years later that would link IL 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 a concurrency with then-IL 159), and up Broadway in Alton until its concurrency with US 67 using Belle Street.

SBI Route 111 originally traveled from Waverly to Alton on modern-day IL 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 US 67 was moved west through Jerseyville, IL 267 took its place north of Medora. Some time after, IL 267 was applied south along with IL 111 on a concurrency.

County	Location	mi	km	Destinations	Notes
St. Clair	Centreville	0.0	0.0	Lake Drive
	Washington Park	1.5	2.4	I-64 – Mt. Vernon, St. Louis	I-64 exit 6
Madison	Fairmont City	4.6	7.4	I-55 / I-70 / US 40 – Chicago, St. Louis	I-55 / I-70 exit 6
	Pontoon Beach	9.2	14.8	IL 162 – Granite City, Troy
		11.8	19.0	I-270 – St. Charles, Effingham	I-270 exit 6
		12.1	19.5	Historic US 66 (Chain of Rocks Road)
	Wood River	19.0	30.6	IL 143 – Alton, Edwardsville
		20.5	33.0	IL 255 – Alton	IL 255 exit 8
	Bethalto	22.6	36.4	IL 140 east – Bethalto	South end of IL 140 concurrency
		22.9	36.9	IL 255 – Godfrey	IL 255 exit 10
	Alton	26.5	42.6	IL 3 south / IL 140 west – Granite City	North end of IL 140 concurrency; south end of IL 3 concurrency
	Godfrey	30.3	48.8	IL 3 north – Grafton	North end of IL 3 concurrency
		30.9	49.7	US 67 south – Alton	South end of US 67 concurrency
		33.4	53.8	US 67 north / IL 267 – Jerseyville	North end of US 67 concurrency; south end of IL 267 concurrency
		33.6	54.1	IL 255
Jersey	No major junctions
Macoupin	​	44.5	71.6	IL 16 – Jerseyville, Gillespie
	Medora	48.7	78.4	IL 267 north – Jacksonville	North end of IL 267 concurrency
	​	60.0	96.6	IL 108 east – Carlinville	South end of IL 108 concurrency
	​	60.9	98.0	IL 108 west – Carrollton	North end of IL 108 concurrency
Morgan	Waverly	82.18	132.26	IL 104 – Jacksonville, Taylorville
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus

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