Illinois Route 128
IL 128 highlighted in red
Route information
Maintained by IDOT
Length	55.57 mi[1] (89.43 km)
Existed	1924[3]–present
Major junctions
South end	I-70 in Altamont[2]
Major intersections	US 40 in Altamont
North end	IL 121 in Dalton City
Location
Country	United States
State	Illinois
Counties	Effingham, Fayette, Shelby, Macon, Moultrie*
Highway system
Illinois State Highway System Interstate US State Tollways Scenic
← IL 127 → IL 129

Illinois Route 128 is a north–south state route in east-central Illinois. It runs from Interstate 70 in Altamont to Illinois Route 121 in Dalton City. This is a distance of 55.57 miles (89.43 km).^[1]

Route description

Illinois 128 is a two-lane, rural surface road for its entire length. Immediately north of Interstate 70, it overlaps U.S. Route 40 for 3 miles (5 km). It is also concurrent with Illinois Route 16 near Shelbyville.

Illinois 128 may or may not run through Moultrie County, depending on its exact routing, as the route appears to run along portions of the Shelby/Moultrie and Macon/Moultrie county lines.

History

SBI Route 128 originally ran from U.S. Route 40 (originally Illinois Route 11) to Illinois 16 west of Shelbyville. In March 1937, it replaced IL 169 north of Shelbyville to Dalton City.^[4] Finally, as Interstate 70 was being built in the 1950s and 1960s, it was extended along U.S. 40 to Altamont.^[3]

Major Intersections

County	Location	mi[5]	km	Destinations	Notes
Effingham	Altamont	0.0	0.0	I-70 – Effingham, St. Louis	I-70 exit 82
		0.8	1.3	US 40 east	South end of US 40 concurrency
Effingham–Fayette county line	​	4.1	6.6	US 40 west – Vandalia	North end of US 40 concurrency
	​	14.5	23.3	IL 33 east – Beecher City
Shelby	​	30.9	49.7	IL 16 west – Pana	South end of IL 16 concurrency
	Shelbyville	34.0	54.7	IL 16 east – Mattoon	North end of IL 16 concurrency
Moultrie	Dalton City	55.57	89.43	IL 121 – Decatur, Mattoon
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus