Interstate 172 Illinois - Interstate Travel Information
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Interstate 172 Illinois

Photo taken by Rich Piehl

Routing

Interstate 172, formerly Illinois 336, provides a freeway spur from Interstate 72/U.S. 36 north to the U.S. 24 interchange near Fowler via Quincy. It facilitates traffic flow through the Quincy area. Now that Interstate 72 in Illinois is complete, Interstate 172 ends at Exit 4 along Interstate 72.

History

AASHTO originally approved the numbering of Interstate 172 along what is now the Interstate 72 corridor between the Illinois 336 (current Interstate 172) east to Interstate 55 near Springfield. While AASHTO approved this routing on October 9, 1991, it was contingent upon Federal Highway Administration approval. The FHWA preferred to designate this route as Interstate 72. Due to this change, the Interstate 172 was moved to the Illinois 336 freeway around Quincy. AASHTO approved the extended Interstate 72 and new Interstate 172 on April 22, 1995.

Future Aspirations

Interstate 172 currently changes into Illinois 336, which continues as an expressway north toward Carthage. It is likely that Illinois 336 will be extended to meet the U.S. 67 corridor. If Illinois 336 is promoted to Interstate standards, Interstate 172 will likely be extended as well.

Mileage

State Mileage Cities Junctions
Illinois 19.69 Quincy Interstate 72
Sources: October 31, 2002 Interstate Route Log and Finders List

Southern Terminus - Interstate 72 and U.S. 36 - Fall Creek, Illinois
Perspective from Interstate 172 south
Southbound Interstate 172, one mile outside of Interstate 72. The final two miles of Interstate 172 is part of the Great River Road system, overtaking the routing between Exit 2/Illinois 57 and Interstate 72. Photo taken by Brian Dowd (08/03/02).
Drawing within one-half mile of Interstate 72 on Interstate 172 southbound. There three miles of Interstate 72 west between Interstate 172 and the Mark Twain Bridge over the Mississippi River into Hannibal, Missouri. Photo taken by Brian Dowd (08/03/02).
An end Interstate 172 shield posted in conjunction with the entrance of the freeway from Adams into Pike County. When Interstate 172 first opened, all traffic was defaulted eastward to Hull on Interstate 72/U.S. 36 eastbound. Photo taken by Brian Dowd (08/03/02).
Interstate 172 ends as traffic splits between Interstate 72 east and west. Two things worth mentioning here. One, U.S. 36 overlaps Interstate 72 between Hannibal and Decatur, yet is omitted from the Interstate 172 guide signage for this exit. Two, the exit numbers 4A/B coincide with the mileage of Interstate 72 from the Missouri state line via the Mark Twain Bridge. It is not uncommon to see exit numbers of an Interstate terminus that utilize the mileage of the intersecting route. See Interstate 195 New Jersey and Interstate 630 Arkansas for more examples of this practice. Photo taken by Brian Dowd (08/03/02).
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Perspective from Interstate 72 west
A left exit connects Interstate 72 and U.S. 36 west with Interstate 172 north; stay right to continue west on Interstate 72 and U.S. 36. Until September 2000, this interchange marked the western end of Interstate 72 and the southern end of Interstate 172 near Quincy, Illinois. With the completion of the new Mark Twain Bridge over the Mississippi River, Interstate 72 was extended into Missouri. Note that the Great River Road system uses both Interstates as it crosses the river between Hannibal and Quincy. Photo taken by Jeff Royston (02/05/08).
Perspective from Interstate 72 east
The first exit of Interstate 72 as it enters Illinois is for Illinois 106/Hull at Exit 1. After leaving the Mississippi River area, Interstate 72 enters farmland en route to Exit 4A/B/Interstate 172 north. The Great River Road system follows Interstate 72/U.S. 36 across the Mississippi River and departs via Interstate 172 to Illinois 57. Top photo taken by Rich Piehl (06/01); Bottom photo taken by Brian Dowd (08/03/02).
Interstate 72/U.S. 36 within one-half mile of the split with Interstate 172 north/Exit 4A. This interchange is the only that we can cite where every traffic movement is considered an exit. This meaning, that each direction of Interstate 72 and the direction of Interstate 172 north is assigned either Exit 4A or Exit 4B. Top photo taken by Rich Piehl (06/01); Bottom photo taken by Brian Dowd (08/03/02).
Interstate 172 begins from Interstate 72/U.S. 36 eastbound and travels 13 miles north to Quincy, providing a route to Macomb via Illinois 336 and U.S. 136, 82 miles to the northeast. Eastbound Interstate 72 signage includes the control point of Pittsfield. The town of 4,450 is featured because it is the county seat of Pike County. Top photo taken by Rich Piehl (06/01); Bottom photo taken by Brian Dowd (08/03/02).
Exit 4A/4B gore point sign on Interstate 72/U.S. 36 eastbound. Photo taken by Brian Dowd (08/03/02).
Perspective from Interstate 172 north
After leaving Interstate 72, this is the first reassurance shield on Interstate 172 north. Photo taken by Jeff Royston (02/05/08).
Northern Terminus - U.S. 24 and Illinois 336 - near Quincy, Illinois
Perspective from Interstate 172 north
End Northbound Interstate 172 and Begin Illinois 336 at Junction U.S. 24 near Fowler. Illinois 336 continues as an expressway with at-grade intersections for several miles, then temporarily terminates. It is planned to extend Illinois 336 northeast to provide an expressway connection to U.S. 34 and Interstate 74. It is unclear if this road will be constructed to Interstate standards, but it seems unlikely at this point. Photo taken by Jeff Royston (02/05/08).
Perspective from U.S. 24 east
Eastbound U.S. 24 approaches the junction with Interstate 172 south and Illinois 336 north. Interstate 172 follows a freeway alignment past Quincy, merging with Interstate 72 just east of Hannibal, Missouri. Illinois 336 travels north as an at-grade expressway, connecting to U.S. 136 near Carthage, with plans to connect Illinois 336 to U.S. 67. Photo taken by Justin Cozart (11/01/03).
Perspective from U.S. 24 west
Westbound U.S. 24 approaches the junction with Interstate 172 south and Illinois 336 north. Photo taken by Jeff Royston (02/05/08).
Perspective from Illinois 336 south
Perspective from Interstate 172 south
This is the first reassurance shield on Interstate 172 south after the U.S. 24 and Illinois 336 interchange. Photo taken by Jeff Royston (02/05/08).

Page Updated April 20, 2008.