Interstate 255 Missouri / Illinois


Interstate 255 is the eastern third of belt system around metropolitan St. Louis. Interstate 255 begins its northerly journey at the southern terminus of Interstate 270 in Mehlville, Missouri, at its junction with Interstate 55. Crossing the Mississippi River into Illinois with U.S. 50 along the Jefferson Barracks Bridge, Interstate 255 turns north after its interchange with U.S. 50. Heading north around East St. Louis, Interstate 255 rejoins Interstate 270 to the west of Glen Carbon, Illinois. This freeway provides a bypass for Interstate 55 for traffic bound from Memphis to Chicago that did not use Interstate 57.

Future Aspirations

Although Interstate 255 ends at Interstate 270, the freeway continues north of Interstate 270 as Illinois 255. Planning for the route commenced in 1988 as I-255 was nearing completion. However the Alton Bypass was not part of federal highway plans, so funding for it would come at the state level.1

The first portion of the IL 255 freeway constructed was the 6.8-miule extension from I-255 north to Illinois 143 (Edwardsville Road). It opened in October 1998 at a cost of $88.7-million. Estimations for the continuation of the freeway north to Godfrey ballooned to $200 million, leading to skepticism that it would ever be built. Lobbying by the Committee For Completion of Highway 255 ushered the public behind the effort, leading to the May 1999 allocation of $180 million for IL 255 by Governor George Ryan.1

Work was slow to begin, and the 7.6-mile $78.1-million stretch between IL 143 and Fosterburg Road in Alton opened in October 2006.1 Construction progressed from there on a $25.1-million 2.75 mile segment to Seminary Road. It was completed in August 22, 2008.2

The next stage of construction kicked off in May 2010 on a $21.9-million project involving 3.4 miles of new roadway through to U.S. 67 in Godfrey.1 The freeway opened between Seminary Road and Humbert Road at Godfrey on October 26, 2012 and from Humbert Road to Illinois 111 (Montclaire Avenue on November 21, 2012.3 This left final work on the "Godfrey Y", the wye interchange with U.S. 67 leading northwest to Jerseyville, which was fully opened by mid-July 2013.4 The entire IL 255 corridor is envisioned as the southern leg of a planned four-lane route along U.S. 67 linking the St. Louis area with the Quad Cities.3

Since the freeway was constructed with state funds, it is not a candidate for Interstate status. However, that also depends upon whether an Interstate-grade facility is constructed along U.S. 67, as some Western Illinois politicians have wanted for years.


The first plan for Interstate 255 took the route northeast from Mehlville, Illinois to Interstates 55 & 70 at Collinsville. The bypass freeway was completed from the Jefferson Barracks Bridge to there in 1986. During that time, state officials successfully convinced the federal government to lengthen the route another six miles to meet Interstate 270 northeast of Pontoon Beach.6 This extension was completed on March 15, 1988 and it included provisions for the eventual Illinois 255 freeway leading north to Alton.7

Missouri went through the Saint Louis region in 2002 and resigned the roads with newer style retroreflective sign panels. The sign erecting process began in the winter of 2000. Therefore many of the below photographs show the before and after results of the project. By late 2001, the Interstate 255/Interstate 270 freeway in Missouri was dedicated the "American Veterans Memorial Highway".

Highway Guides

Southern Terminus - Interstates 55 and 270 - Mehlville, Missouri
Perspective from Interstate 255 south/west
Illinois 3 intersects with Interstate 255 at Exit 6, about two miles east of the Mississippi River. Note that Interstate 255 is signed north-south in Illinois, while it is signed east-west in Missouri. Illinois 3 merges onto northbound Interstate 255 along with the Great River Road, and U.S. 50 is cosigned with Interstate 255 in both directions from this interchange. Photo taken by Joel Wade (04/16/05).
Interstate 255 and U.S. 50 cross the Mississippi River via the Jefferson Barracks Bridge, thus leaving the Land of Lincoln and entering the Show Me State of Missouri. This bridge is a tied arch bridge, parallel span. The westbound bridge was constructed first, in 1984; the eastbound bridge was opened two years later, in 1986. Photo taken by Joel Wade (04/16/05).
This photo shows westbound Interstate 255 and U.S. 50 about 2.5 miles prior to the handover of the Interstate 270 designation from Interstate 255. U.S. 50 will leave Interstate 255 at the Lindbergh Blvd exit. Photo taken by Brian Dowd (06/02).
The first exit along westbound Interstate 255 and U.S. 50 in Missouri after the Jefferson Barracks Bridge over the Mississippi River is Exit 3 Koch Road, followed by Exit 2, Junction Missouri 231/Telegraph Road. Photo taken by Joel Wade (04/16/05).
The next exit along westbound Interstate 255 and U.S. 50 is Exit 2, Junction Missouri 231/Telegraph Road, followed by Exit 1D, Junction U.S. 50-61-67 southwest. Photo taken by Joel Wade (04/16/05).
Guide Sign on westbound Interstate 255/U.S. Route 50 1.75 miles before Interstate 55. Odd that this sign (which appears to be a new retroreflective panel) refers to the Interstate 55 junction as EXIT 1 as it would be better qualified as EXITS 1 A-B. Photo taken by Brian Dowd (06/02).
MoDOT gets the exit number correct on this Interstate 55 guide sign. The Lindbergh Blvd sign technically should read U.S. 50 West/To U.S. 61/U.S. 67 since traffic does not get to U.S. Routes 61/67 for about one-third a mile north of the exit. Photo taken by Brian Dowd (06/02).
Another view of the sign bridge on Interstate 255 westbound at Exit 1D/Lindbergh Boulevard. Photo taken by Rich Piehl (12/00).
Upcoming exits sign, posted only three-fourths of a mile before the Interstate 55/270 junction. 274 miles to the south, is the Interstate 55 control city of Memphis. Only 103 miles away is Cape Girardeau. Photo taken by Brian Dowd (06/02).
Nearing the Interstate 55 junction, with the right-hand lane becoming an exit-only allocation for Exits 1A-B. Downtown Saint Louis sits just 11 miles north of this interchange. Photo taken by Brian Dowd (06/02).
The final two signs leading to northbound Interstate 270 from westbound Interstate 255. It should be said that the exit numbering for Interstate 55 on Interstate 255/Interstate 270 is a little odd. It does not matter which direction you approach the interchange, the first exit is Exit 1A, and the second is Exit 1B. Since both highways share a common milepost 0, this makes little sense. This violates the standard numbering convention where the suffixes of a numbered interchange should be in alphabetical order from milepost 0 eastward or northward. Therefore, the signage on Interstate 255 westbound is backwards. This is not the only location where this anomaly occurs, as Louisiana exit numbering conventions on Interstate 10 westbound in the Baton Rouge and New Orleans area is also backwards. Photos taken by Brian Dowd (06/02).
Here is a more recent view of the signage on westbound Interstate 255 as it reaches Exits 1A-B for the Junction with Interstate 55. Note that the signs have been changed since 2002: (1) the exit numbers A and B have been swapped and (2) the WEST directional banner for the Interstate 270 pull-through sign has been removed. Photo taken by Joel Wade (04/16/05).
Interstate 270 Milepost Zero paddle at the Interstate 55/255 interchange. Photo taken by Rich Piehl (12/00).
Perspective from Interstate 270 south
First glimpse of the Interstate 55 and U.S. Routes 61/67 interchange, 4.25 miles to the north via Interstate 270 southbound. Photo taken by Brian Dowd (06/02).
2.25 miles before the termini. This upcoming exits sign gives a clue that there really is no end to the freeway at the two termini. An exit for S.R. 231/Telegraph road is a couple miles after Interstate 55. Photo taken by Brian Dowd (06/02).
Notice this Interstate 55 panel explicitly calls this EXIT 1 A-B (even though it should read EXITS 1 A-B) versus the EXIT 1 in the next photo by Rich. Photo taken by Brian Dowd (06/02).
Interstate 55 overhead on Interstate 270 south at the Missouri 21 exit. Note that the right-hand panel has since been replaced. Photo taken by Rich Piehl (12/00).
Interstate 270 Ends signage. Notice that the transition to Interstate 255 is mentioned. Photo taken by Rich Piehl (12/00).
Interstate 55 and U.S. 61/67 sign bridge on Interstate 270 southbound. Photo taken by Rich Piehl (12/00).
Replacement of the sign-panel in the above photobox. Photo taken by Brian Dowd (06/02).
A collector-distributor lane takes traffic to both Interstate 55 and the U.S. 61/67 overlap. Meanwhile the travel lanes for Interstate 270 commit to Interstate 255. Photo taken by Brian Dowd (06/02).
The sign bridge in the background of the above photograph displays these guide signs for Exits 1A/B/C and the Interstate 270 collector/distributor roadway. Exit 1C serves the Mehlville area. Photo taken by Brian Dowd (06/02).
This photo shows the southern terminus of Interstate 270 (same signage in the above photograph). At this location, traffic continues east on Interstate 255 toward the Jefferson Barracks Bridge and the state of Illinois. Photo taken by Rich Piehl (12/00).
The interchange between Interstate 255/Interstate 270 and Interstate 55, which used to be total cloverleaf, now contains six directional ramps and two loop ramps. The traditional diamond ramps from Interstate 270 south to Interstate 55 south, Interstate 55 north to Interstate 255 east, Interstate 255 west to Interstate 55 north and Interstate 55 south to Interstate 270 north are accompanied by two directional flyovers from Interstate 55 north to Interstate 270 north and Interstate 55 south to Interstate 255 east while the ramps from Interstate 270 south to Interstate 55 north and Interstate 255 west to Interstate 55 south are loop ramps. Photo taken by Brian Dowd (06/02).
Traffic has two options for exiting onto U.S. Routes 61/67 off of the American Veterans Memorial Highway. First traffic can exit going from this ramp built into the Interstate 55 ramps to a southbound facing ramp to Lemay Ferry Road, or traffic can pass the Interstate 55 ramp system and exit onto a loop ramp which will put them facing northward to Lemay Ferry Rd just to the east of where the first ramp connects. The sign bridge in the background is for the traffic from Interstate 55 headed to Interstate 255 eastbound. Signage leading to the second exit to Lemay Ferry Road is also built into that ramp. Photo taken by Brian Dowd (06/02).
The overhead guide signs Pictured in the background of the above photograph. Photo taken by Brian Dowd (06/02).
Perspective from Interstate 55 north
This photograph shows a pretty typical panel on the arteries feeding into the beltway giving MoDOT's best effort to guide traffic that is attempting to get around the city. From Interstate 55, the fastest way to get to Illinois is to take Interstate 255 East. Similar signs are on Interstate 70 west of Missouri 370 (recommending drivers take Route 370 East to I-270 East to Illinois), Eastbound Interstate 44 (recommending drivers take I-270 South to I-255 to Illinois) and on Westbound Interstate 270 (alerting drivers that Route 370 West is an alternate for Westbound I-70 drivers heading to Wentzville and Kansas City). Photo taken by Brian Dowd (10/12/02).
This centerline panel is two miles before Interstate 270 and Interstate 255 and omits any mention of I-255. If memory serves Brian correct this sign is button copy and might predate the Interstate 255 designation (or could be a copy/replacement of a sign that did). Photo taken by Brian Dowd (10/12/02).
Five lanes of Interstate 55 northbound lanes just 1.50 miles before the Interstate 270/I-255 interchange (Exit 196A-B). Photo taken by Brian Dowd (10/12/02).
0.75 milea before the splitoff for the American Veterans Memorial Highway, these EXIT ONLY lane assignment signs make their appearance. This is also a typical assembly for MoDOT in which each lane gets its own individual sign panel, instead of a single sign covering both directions like INDOT does on Southbound Interstate 65 at Interstate 465 on Indianspolis' Southside. Photo taken by Brian Dowd (10/12/02).
A second perspective of the Interstate 255/270 overheads on Interstate 55 north. Kansas City is 241 miles west via Interstate 270/70 while the state capital of Columbia is 124 miles apart. Photo taken by Rich Piehl (12/07/00).
This centerline distance sign is 1/4 mile before the I-270/I-255 splitoff. This give a good view of how the freeway looks. I-55 was recently redone south of here all the way to Route M in Jefferson County. The project, which had a few stumbling blocks along the way, was deemed a success by MoDOT since the bond financed project came in on time and 2% under budget. Photo taken by Brian Dowd (10/12/02).
These signs attached to the Mattis Rd overpass in South St. Louis County are just past the 1/4 mile point before the beltway. Again, these signs are typical MoDOT assembly with separate signs for each lane, and the more condensed E series numbering in the 3di shields. Photo taken by Brian Dowd (10/12/02).
A second gander at the Exit 196A/B overheads as seen almost two years prior. Interstate 55 northbound continues with four through lanes beyond the Interstate 255/270 ramp departure. Photo taken by Rich Piehl (12/07/00).
At the gore for the Interstate 270/255 ramps. Even though Interstate 270 is marked here as going West, the directions are marked East-West to reduce confsion, as MoDOT consideres Interstate 270 as going Northbound (as shown by the first trailblazer) from Interstate 55 and Interstate 255 goes Eastbound. A closer inspection of the gore sign reveals that it is marked as Exit 196, the A/B suffix were added in 2000 by MoDOT when the signs were replaced at the request of the planning commission. All Interstate to Interstate interchanges had suffixes added to these stack ramps. This interchange design is kind of interesting. It is best described as a cloverstack. The ramps from Interstate 55 to Interstate 270/255 include stack flyovers, but the ramps from I-255 and I-270 include the legacy loop ramps for left movements. To the north is a single point urban interchange with U.S. Routes 50/61/67/Lindbergh Blvd which mixes with a collector distributor system between the exits. Photo taken by Brian Dowd (10/12/02).
Past the gore point the two respective ramps diverge. The two lane flyover to Interstate 270 Northbound will connect with traffic heading to Interstate 270 Northbound from Southbound Interstate 55 before merging onto the freeway to the west suburbs. Traffic exiting onto Interstate 255 East will have the oppurtunity to exit onto U.S. Routes 61/67/Lemay Ferry Rd before merging with traffic coming from Interstate 55 Southbound and merging into Interstate 255 Eastbound. Also of note: The typical center West I-270 [left arrow]/East I-255 [right arrow] is replaced here with an Exit 196B gore sign. Photo taken by Brian Dowd (10/12/02).
Two years prio, the same Interstates 255 and 270 sign bridge on the ramp from Interstate 55 north. Interstate 255 connects with Interstate 55 again at Exit 25, with another 276 miles between the next meeting and the Windy City. Photo taken by Rich Piehl (12/07/00).
Perspective from Interstate 55 south
Advance signage for Interstate 255 and 270 at Exit 199 on Interstate 55 south. Photo taken by Rich Piehl (12/00).
Interstate 55 southbound approaching the junction with Interstate 255/270 and U.S. 50/61/67. Photo taken by Rich Piehl (12/00).
Interstate 255 east/Interstate 270 west sign bridge for Exits 196A/B on Interstate 55 southbound. This assembly is posted after the ramps depart from the mainline of Interstate 55. The Interstate 55 south to Interstate 255 east is a flyover. Photo taken by Brian Dowd (06/02).
Same sign bridge as Pictured in the above photograph. Photo taken by Rich Piehl (12/00).
Northern Terminus - Interstate 270 and Illinois 255 - near Glen Carbon, Illinois
Perspective from Interstate 255 north
This sign bridge, one mile from the terminus with Interstate 270, indicates the upcoming transition to Illinois 255 of Interstate 255. Photo taken by Rich Piehl (12/00).
Four northbound lanes of Interstate 255 approaching Interstate 270/Exit 30. The left-hand three lanes become Illinois 255, while the right-hand is exit-only for Interstate 270. Photo taken by Rich Piehl (12/00).
The northern terminus of Interstate 255 occurs at the Exit 30 departure for Interstate 270. Illinois 255 continues six miles or so northward to its terminus at Illinois 143/Edwardsville Road. Wood River and Alton lie westward via Illinois 143. Photo taken by Rich Piehl (12/00).
Partition of the Interstate 270 ramps from Interstate 255 northbound. A sweeping flyover shuttles traffic to Interstate 270 westbound carrying two lanes. The bypass reaches Interstate 70 in 20 miles at Bridgeton, Missouri. Photo taken by Rich Piehl (12/00).
Perspective from Illinois 255 south
Southbound Illinois 255 sign bridge, one mile in advance of the Interstate 255 terminus and Interstate 270 interchange. Note that Illinois 255 utilizes the Interstate 255 exit number of 30 for this partial cloverleaf interchange. Photo taken by Brian Dowd (05/02).
One-half mile from the transition to Interstate 255 from Illinois 255 southbound. Long-distance control cities are used for all available directions of Interstate 255 and 270. Photo taken by Brian Dowd (05/02).
Interstate 255 southbound begins and Illinois 255 ends. Exit 30 traffic utilizes a collector/distributor roadway from this southbound freeway. Photo taken by Brian Dowd (05/02).
Exit 30 southbound c/d roadway at Interstate 270 westbound. Kansas City lies 241 miles to the west via Interstate 270 and 70. Photo taken by Brian Dowd (05/02).
Last Illinois 255 southbound exit for Interstate 270 eastbound. 221 miles separate this interchange from the capital city of Indiana. Photo taken by Brian Dowd (05/02).
Perspective from Interstate 270 east
Interstate 255/Illinois 255 - Exit 7 guide sign on Interstate 270 eastbound, 1.75 miles out. The upcoming interchange is a modified cloverleaf with the ramp from Interstate 255 north to Interstate 270 west consisting of a flyover. The eastbound Interstate 270 ramps for Interstate 255/Illinois 255 are typical cloverleaf ramps accessible by a collector/distributor roadway. Photo taken by Brian Dowd (05/02).
Eastbound on Interstate 270 at Exit 6B/Illinois 111 north. The Illinois 255 freeway extension north from Interstate 270 alleviated traffic concerns to the Wood River an d Alton vicinities. Photo taken by Rich Piehl (12/00).
Nearing the Exit 7 - C/D lane on Interstate 270 eastbound. The control points for Interstate 255 consist of Memphis, Tennessee (for the return to Interstate 255 south of Saint Louis), and Wood River for the current north end of the Illinois 255 freeway. Photo taken by Rich Piehl (12/00).
Split of Interstate 270 eastbound from the Interstate 255/Illinois 255 collector/distributor roadway. The control point for Interstate 270 is Indianapolis, as the bypass route reunites with its parent eight miles to the east. Photos taken by Brian Dowd (05/02).
Interstate 255 sees its southbound beginning from the Exit 7 collector/distributor roadway in this photograph. Just five miles to the south Interstate 255 crosses its parent (along with Interstate 70) at Collinsville. Photo taken by Brian Dowd (05/02).
Second view of the Interstate 255 southbound ramp and signage from the Exit 7 c/d roadway on Interstate 270 east. A 298 mile journey lays ahead for Memphis bound travelers to cross the Mississippi River into Tennessee. Photo taken by Rich Piehl (12/00).
Interstate 270 eastbound cloverleaf ramp for Illinois 255 north. The freeway extension from Interstate 255 travels approximately six miles to the north serving the outskirts of the Alton community. Photo taken by Brian Dowd (05/02).
Perspective from Interstate 270 west
One mile advance guide sign for Interstate 255/Illinois 255 on Interstate 270 westbound. The mileage sign indicates the distance to Exits 6B/A - Illinois 111, and the Interstate 70 control cities of Columbia and Kansas City. The 262 mileage figure for Kansas City reflects the distance to downtown. Photo taken by Rich Piehl (12/00).
Exit 7B for Illinois 255 north departs Interstate 270 westbound in this photograph. Interstate 270 will travel through Granite City in four miles and the Mississippi River in seven. Photo taken by Brian Dowd (05/02).
Another view of the sign bridge on Interstate 270 westbound at Illinois 255 north. Photo taken by Rich Piehl (12/00).
Interstate 270 westbound at Exit 7A/Interstate 255 southbound. Exits 6B/A for Illinois 111/Wood River/Pontoon Beach lie one mile ahead. Photo taken by Rich Piehl (12/00).


  1. "Metro East area is in the loop - 21-mile, four-lane freeway will arc from I-270 and link to U.S. 67 near Godfrey." St. Louis Post-Dispatch, July 14, 2010.
  2. "Illinois 255 extends its reach to Godfrey." Edwardsville Intelligencer, August 26, 2008.
  3. "Illinois 255 opens to Godfrey 'Y'." The Telegraph (Alton, IL), November 22, 2012.
  4. "Routes 67 and 255 Come Together." Alton Daily, July 19, 2013.
  5. "I-255 RIM MEANS LOOP IS FINISHED - FOR NOW." St. Louis Post-Dispatch, July 31, 1988.
  6. "ONE-MILE PIECE OF I- 255 WILL OPEN TODAY." St. Louis Post-Dispatch, March 15, 1988.

Page Updated November 22, 2013.

More Info


State Missouri
Mileage 3.77
Cities St. Louis metro
Junctions I-55, I-270
State Illinois
Mileage 27.05
Cities East St. Louis metro
Junctions I-55/70, I-270
TOTAL 30.82
Source: December 31, 2016 Interstate Route Log and Finders List