|Central Illinois Expressway|
|Maintained by IDOT|
|Length:||19.69 mi (31.69 km)|
|Existed:||1995 – present|
|South end:||I-72 / US 36 / IL 110 in Hull|
|North end:||US 24 / IL 110 / IL 336 in Quincy|
Interstate 172 (I-172) is a spur route from Interstate 72. The highway runs north from its start outside of Hannibal, Missouri to just two miles (3 km) west of Fowler, Illinois. At U.S. Highway 24, Interstate 172 becomes Illinois Route 336, which runs north and east to Macomb, Illinois via Carthage, Illinois. The entire portion of I-172 and I-72 from I-172 east to Springfield is also known by its former name, the Central Illinois Expressway. I-172 is 19.69 miles (31.69 km) long.
Interstate 172 begins at an trumpet interchange with its parent route, I-72, about five miles east of Hannibal, MO, before immediately crossing into Adams County. I-172 enters the Quincy area at exit 10 (State Route 96), passing to the far east of the city. I-172 ends just northeast of Quincy, ending at US 24, continuing north as State Route 110/336.
Interstate 172 originally was what Interstate 72 is now from Springfield, Illinois to the current interchange with I-172. This was approved by the American Association of State Highway and Transportation Officials (AASHTO) on June 9, 1991.
On April 23, 1995, after a re-examination by the Federal Highway Administration, the highway to Hannibal was redesignated I-72, with the highway north to Quincy, Illinois redesignated as Interstate 172. The highway is non-chargeable, meaning that even though it is an Interstate, it was not built with federal funds.
After Interstate 172 was completed, the Illinois Department of Transportation continued development of the four-lane highway as Illinois Route 336. Construction is ongoing (2013) the 4-lane highway is complete to a terminus interchange with U.S. 136 just west of Macomb, Illinois. In 2013, grading and earth work has begun on a Macomb bypass. This construction is expected to take 2 to 3 years to complete, due to state funding and bridge construction required over the east branch of the LaMoine River.
|Pike||Levee Township||0.00||0.00||0||I-72 / US 36 / IL 110 west / Great River Road south – Springfield||Southbound exit and northbound entrance, exit 0 is for 72 west|
|Adams||Fall Creek Township||3.18||5.12||2||IL 57 – Marblehead, Quincy|
|Melrose Township||10.52||16.93||10||IL 96 (Payson Street, 36th Street) – Quincy|
|Quincy||14.47||23.29||14||IL 104 / Broadway – Quincy||Serves Quincy Airport|
|Ellington Township||15.90||25.59||15||Columbus Road, Wismann Lane|
|19.69||31.69||19||US 24 to IL 96 – Mount Sterling, Keokuk|
|IL 110 east / IL 336 north – Macomb||Continuation beyond US 24|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi
- Schoenburg, Bernard (1995-04-28). "Road to the top? Designation puts expressway in the 'big leagues'". The State Journal-Register (Springfield, IL).
- Illinois Technology Transfer Center (2007). "T2 GIS Data". Retrieved 2007-11-08.
- Kurumi. Interstate x72. Last updated November 20, 2005. Retrieved May 14, 2006.