I-72 runs for just over two miles (3.2km) in the state of Missouri. Its western terminus is an interchange with US61 to the Mark Twain Memorial Bridge over the Mississippi River. This bridge connects the city of Hannibal with Illinois. Presently, there are only two exits for I-72 in Missouri, only one of which is numbered
At its eastern terminus in Champaign, I-72 continues as Church Street (westbound) and University Avenue (eastbound), which stay as one-way streets for an additional three miles (4.8km) into downtown Champaign.
After discussions regarding extending an Interstate Highway through the state of Missouri, on April 22, 1995, AASHTO approved another renumbering. I-172 was renumbered in its entirety as I-72. The US36 extension west of Fall Creek was also given the I-72 designation. The Illinois Route 336 (IL336) expressway was renumbered to I-172 from Fall Creek to Fowler.[3][4]
Prior to September 2000, Mark Twain Avenue (old US36) was composed of the current Mark Twain Avenue (now Route79) and the portion of I-72 and US36 west of exit157 to the Hannibal city limits. Route79 terminated at the foot of the old Mark Twain Memorial Bridge at the corner of Third Street and Mark Twain Avenue. Signs along the four-lane expressway portion of Mark Twain Avenue marked the route as "Future I-72", while signs along what is now Route79 had I-72 trailblazers to direct drivers to the temporary terminus at Fall Creek, Illinois. When the new Mark Twain Memorial Bridge was completed in September 2000, I-72 was routed over the new bridge, along with US36. Route79 was extended along Mark Twain Avenue to terminate at exit157.
Based on the 157-mile (253km) marker at Route79, if/when US36 is upgraded to Interstate standards across Missouri, the future western terminus of I-72 would be at Cameron at the intersection with I-35. Currently, the west end of I-72 route is west of US61 and flows concurrent with US36 into Illinois. In 2004, US36 was upgraded to a four-lane expressway between US61 and US24 at the Rocket Junction (seven miles (11km)). There are three exits along this expressway: Veterans Road, Shinn Lane (Hannibal Regional Hospital), and US24 east at the Rocket Junction. Also, an interchange with Route15 was installed in Shelbina.
Due to funding priorities, upgrading US36 between Macon and Hannibal was a low-priority project and was shelved. The Missouri Department of Transportation (MoDOT) committed to constructing the four-lane highway as an at-grade expressway only if the five counties served by US36 east of Macon would contribute half of the $100 million (equivalent to $140million in 2024[5]) cost. Road construction to complete the 52.4 miles (84.3km) between Hannibal and Macon began in 2007. In August 2010, the four-lane expressway was completed from Macon to Hannibal, completing Missouri's portion of the Chicago–Kansas City Expressway.[6]
Future
Plans exist to extend I-72 westward from its current terminus in Hannibal to St. Joseph, Missouri along the existing US 36, but the proposal was shelved for years despite most of the route being a part of the Chicago–Kansas City Expressway. In May 2023, Missouri lawmakers approved a $2.5 million study on the conversion of US 36 into I-72.[7] The extension of I-72 is seen as a way to relieve the pressure off of I-70 as well as reduce truck traffic in St. Louis.[8][9] However, in July 2023, the bill was vetoed by Governor Mike Parson who said that it was not the right time to run the study.[10] The extension to I-29 is listed under High Priority Corridor 61B, although part of it was for the CKC and not I-72.[11]
Western end of I-55 concurrency; signed as exit 97A (south) and 97B (north) eastbound; signed as exit 92A (north) westbound; westbound I-72 exits southbound I-55 via exit 92B
Eastern end of I-55 concurrency; I-72 eastbound exits I-55 via exit 98A, I-72 westbound exits itself via exit 103A; IL 97 signed as exit 98B eastbound; northbound I-55 signed as exit 103B westbound
Interstate172 (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 IL110. The highway runs north from its start outside of Hannibal, Missouri, to about 2.5 miles (4.0km) west of Fowler. At US24, I-172 becomes Illinois Route 336 (IL336), 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.
Interstate72 Business (I-72) is a business loop of I-72 in Jacksonville. It runs from the I-72/US36/US67 interchange southwest of Jacksonville north along the US67 bypass of Jacksonville to the former alignment of US36 (Morton Avenue). On Morton Avenue, I-72 Bus. runs east through downtown Jacksonville until it reaches I-72 at exit68. This is a distance of 9.5 miles (15.3km).[13]
Major intersections
The entire route is in Morgan County.
↑North Central District (2007). "U.S. 36 4-Laning Project: Contract Awarded for Route 36 Four-lane Project from Shelbina to Macon" (Press release). Missouri Department of Transportation.[full citation needed]
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