{{short description|Interstate Highway in Illinois}} {{redirect|I-172|the Japanese submarine ''I-172''|Japanese submarine I-72}} {{Use mdy dates|date=April 2022}} {{Use American English|date=April 2022}} {{Infobox road |state=IL |route=172 |type=I |map={{maplink-road|from=Interstate 172.map}} |map_custom=yes |map_notes=I-172 highlighted in red |established=1995 |length_mi=19.69 |length_ref=<ref name="t2">{{cite web |author=Illinois Technology Transfer Center |url=http://www.dot.state.il.us/gist2/select.html |title=T2 GIS Data |access-date=2007-11-08 |year=2007}}</ref> |spur_type=I |spur_of=72 |direction_a=South |terminus_a={{Jct|state=IL|I|72|US|36|CKC}} near Hull |direction_b=North |terminus_b={{Jct|state=IL|US|24|CKC||IL|336}} near Quincy |counties=Pike, Adams |previous_type=IL |previous_route=171 |next_type=IL |next_route=172 }} '''Interstate 172''' ('''I-172''') is a spur route, the only auxiliary route of I-72. It is located entirely within the US state of Illinois and is completely concurrent with IL 110. The highway runs north from its start outside of Hannibal, Missouri, to about {{Convert|2.5|mi|km}} west of Fowler. At U.S. Route 24 (US 24), I-172 becomes Illinois Route 336 (IL 336), which runs north and east to Macomb via Carthage. 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.<ref name="schoenburg_1995">{{cite news |title=Road to the top? Designation puts expressway in the 'big leagues' |last=Schoenburg |first = Bernard |date=1995-04-28 |work=The State Journal-Register |location = Springfield, Illinois |url=http://docs.newsbank.com/openurl?ctx_ver=z39.88-2004&rft_id=info:sid/iw.newsbank.com:NewsBank:SJRB&rft_val_format=info:ofi/fmt:kev:mtx:ctx&rft_dat=0EB1485776342992&svc_dat=InfoWeb:aggregated4&req_dat=AA98CDC331574F0ABEAFF732B33DC0B2}}</ref> I-172 is {{convert|19.69|mi|km}} long.<ref name="t2" />
==Route description== I-172 begins at a trumpet interchange with I-72/US 36, about {{convert|5|mi|km|spell=in}} east of Hannibal before immediately entering Adams County while concurrent with IL 110 (Chicago–Kansas City Expressway). I-172 enters the Quincy area at exit 10 (IL 96), passing to the far east of the city. I-172 ends just northeast of Quincy, ending at US 24, continuing north as IL 110/IL 336.
==History== I-172 originally was what I-72 is now from Springfield 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 reexamination by the Federal Highway Administration (FHWA), the highway to Hannibal was redesignated I-72, with the highway north to Quincy redesignated as I-172. The highway is non-chargeable, meaning that, even though it is an Interstate (designed and constructed to Interstate Highway standards and specifications), it was not built with federal funds.<ref>{{cite web |author = Kurumi |url = http://www.kurumi.com/roads/3di/ix72.html |title = Interstate x72 |date = November 20, 2005 |work = Kurumi |access-date = May 14, 2006 }}{{sps|certain=yes|date=April 2022}}</ref> {{-}}
==Exit list== {{Jcttop|exit|length_ref=<ref name="t2" />}} {{ILint|exit |county=Pike |location=Levee Township |ctdab=Pike |mile=0.00 |exit=0 |road={{Jct|state=IL|I|72|US|36|CKC||dir3=West|GRR|dir4=south|city1=Springfield|location2=Hannibal|location3=Kansas City}} |notes=Southbound exit and northbound entrance; southern terminus, exit 0 is for 72 west; exit 4 eastbound/4A westbound on I-72. }} {{ILint|exit |county=Adams |cspan=5 |location=Fall Creek Township |ctdab=Adams |mile=3.18 |exit=2 |road={{Jct|state=IL|IL|57|city1=Marblehead|city2=Quincy}} }} {{ILint|exit |location=Melrose Township |ctdab=Adams |mile=10.52 |exit=10 |road={{Jct|state=IL|IL|96|name1=Payson Street, 36th Street|city1=Quincy}} }} {{ILint|exit |location=Quincy |mile=14.47 |exit=14 |road={{Jct|state=IL|IL|104|road|Broadway|city1=Quincy}} |notes=Serves Quincy Airport }} {{ILint|exit |location=Ellington Township |lspan=2 |ctdab=Adams |mile=15.90 |exit=15 |road=Columbus Road, Wismann Lane }} {{ILint|exit |mile=19.69 |exit=19 |road={{Jct|state=IL|US|24|to2=to|IL|96|city1=Mount Sterling|location2=Keokuk}}<br/>{{Jct|state=IL|CKC||IL|336|dir1=east|dir2=north|city1=Carthage|city2=Macomb}} |notes=Roadway continues as IL 110/IL 336 }} {{Jctbtm|exit}}
==See also== *{{portal-inline|U.S. roads}} *{{portal-inline|Illinois}}
==References== {{Reflist}}
==External links== {{Attached KML|display=inline,title}} *{{ccat-inline}}
72-1 72-1 1 Category:Transportation in Pike County, Illinois Category:Transportation in Adams County, Illinois