U.S. Route 51 in Illinois

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U.S. Route 51

US 51 highlighted in red, former alignment in blue
Route information
Maintained by IDOT and ISTHA
Length415.95 mi[1] (669.41 km)
Length may include both directions of route where it is routed along one-way streets.
Major junctions
South end US 51 / US 60 / US 62 near Wickliffe, KY
Major intersections I-57 / IL 3 near Cairo

I-64 near Richview
I-70 at Vandalia
I-72 at Decatur
I-55 / I-74 at Bloomington
I-39 / I-55 at Normal
I-80 at La Salle

I-88 Toll / IL 110 (CKC) at Rochelle

I-90 Toll at Cherry Valley

I-39 / I-90 at South Beloit
North end US 51 at the Wisconsin state line in South Beloit
CountryUnited States
CountiesAlexander, Pulaski, Union, Jackson, Perry, Washington, Jefferson, Marion, Fayette, Shelby, Christian, Macon, DeWitt, McLean, Woodford, Marshall, LaSalle, Lee, Ogle, Winnebago
Highway system
IL 50 US 52

U.S. Route 51 (US 51) in the U.S. state of Illinois, is a main north–south artery that runs from the Ohio River north to the Wisconsin border, a distance of 415.95 miles (669.41 km).[1]

Route description

Southbound US 51 approaching the town of Cairo

US 51 enters Illinois from Kentucky at the city town of Cairo, Illinois. The highway heads northbound to a village near Cairo called Mounds, and begins to overlap Interstate 57 (I-57), following it for 24 miles (39 km) to Dongola, before splitting and heading north. The highway remains two lanes wide from Dongola to Assumption with the exception of a 10-mile (16 km) section between Centralia and I-64.

Past Assumption, US 51 becomes an expressway to Decatur. In Decatur, US 51 follows I-72 to bypass the city. US 51 leaves I-72 after eight miles (13 km), and it heads north to BloomingtonNormal as an expressway. At Bloomington–Normal, US 51 follows I-74 for a mile, then I-55 for seven miles (11 km), before following I-39 for 140 miles (230 km).

US 51 follows I-39, intersecting I-80 and I-88 along the way. The highway also follows US 20 south of Rockford (while still following I-39). I-39/US-51 join I-90, making US 51 one of the few toll highways in Illinois that is a U.S. Highway. US 51 exits I-39/I-90 just a mile south of the Wisconsin state line. Then US 51 follows Illinois Route 75 (IL 75) west to the intersection of IL 251, and then turns north through South Beloit, Illinois to enter Wisconsin.


US 51 was established in Illinois in the 1920s. Over the years, it became a heavily traveled highway, often experiencing many accidents, particularly in the northern half of the state. This highway gained the moniker of "Killer 51". As a result of these problems, Illinois pushed for a new four lane highway along the corridor. One was proposed in the 1960s and 1970s as part of a proposed supplemental freeway system, but only the area between Rockford and Decatur was given a high priority.[2]

In the 1980s and early 1990s, US 51 was rebuilt to Interstate standards between Rockford and BloomingtonNormal on a new alignment. This new highway became Interstate 39, and US 51 was rerouted onto it. In addition, north of Rockford, US 51 was rerouted onto the existing I-90 segment between South Beloit and Cherry Valley. Most of the old highway became IL 251.

South of Bloomington–Normal to Decatur, US 51 remained largely on the original alignment, and it was expanded to an expressway. In the 2000s, the expressway was continued southward from Decatur to Assumption, Illinois.

Major intersections


US 51 south / US 60 east / US 62 east / Great River Road south – Wickliffe
US 51/US 60/US 62 continue into Kentucky

US 60 west / US 62 west to I-57 south – Charleston
Northern end of US 60/US 62 concurrency

IL 37 north / IL 3 begins – Mound City
Southern terminus of IL 37; southern terminus of IL 3; southern end of IL 3 concurrency

IL 3 north / Great River Road (National Route) – Olive Branch

I-57 south – Sikeston, MO
Northern end of IL 3 concurrency; southern end of I-57 concurrency
Pulaski11.418.38Mounds Road
21.434.418Ullin Road
UnionDongola28.245.424Dongola Road
I-57 north – Chicago
Northern end of I-57 concurrency; northbound exit and southbound entrance
Anna36.057.9 IL 146 – Jonesboro, Vienna
JacksonCarbondale55.088.5 IL 13 – Murphysboro, Marion
De Soto61.398.7 IL 149 – Murphysboro, Hurst
PerryDu Quoin72.4116.5
IL 14 east – Christopher
Western terminus of IL 14
IL 152 west – Pyatts
Eastern terminus of IL 152
Sunfield80.4129.4 IL 154 – Red Bud, Sesser
IL 15 west – East St. Louis
Western end of IL 15 concurrency
IL 15 east – Mount Vernon
Eastern end of IL 15 concurrency
Richview105.7170.1 I-64 – Mount Vernon, East St. LouisI-64 exit 61
IL 177 west – Belleville
Western terminus of IL 177
JeffersonNo major intersections
MarionCentralia116.2187.0 IL 161 – New Baden, Kell
US 50 west – Carlyle
Western end of US 50 concurrency
US 50 east – Salem
Eastern end of US 50 concurrency

US 40 east / IL 185 east – Bluff City
Eastern end of US 40/IL 185 concurrency

US 40 west / IL 185 west – Taylor Springs, Mulberry Grove
Western end of US 40/IL 185 concurrency
148.7239.3 I-70 – Effingham, St. LouisExit 63 on I-70
ShelbyNo major intersections
IL 16 west – Hillsboro
Western end of IL 16 concurrency
IL 29 north – Taylorville
Southern terminus of IL 29
IL 16 east – Shelbyville
Eastern end of IL 16 concurrency
ShelbyNo major intersections
Macon207.3333.6Elwin, Mt ZionNorthbound exit, southbound entrance
210340Decatur, Elwin, Mt ZionInterchange
211.2339.9 IL 48 – Taylorville, Decatur
I-72 west / US 36 – Springfield, Decatur
Southern end of I-72 concurrency; signed as exits 133A (east) and 133B (south)
Decatur219.2352.8138 IL 121 – Decatur, Lincoln
I-72 east – Champaign, Urbana, Decatur
Northern end of I-72 concurrency

US 51 Bus. north – Clinton
239.5385.4 IL 54 – Springfield, Clinton
240.0386.2 IL 10 – Lincoln, Clinton

US 51 Bus. south – Clinton
McLeanHeyworth251.9405.4 US 136 – McLean, Rantoul
US 51 Bus. (Main Street) – Bloomington

I-74 east – Champaign
Southern end of I-74 concurrency
I-55 south – St. Louis, Springfield
Southern end of I-55 concurrency
I-55 BL north (Veterans Parkway)
Signed as exit 134B (north) southbound
265.5427.3160 US 150 / IL 9 (Market Street) – Pekin
I-74 west – Peoria
Northern end of I-74 concurrency
I-55 north – Chicago

I-39 begins
Northern end of I-55 concurrency; southern end of I-39 concurrency; southern terminus of I-39; I-55 exit 164

US 51 Bus. south – Bloomington, Normal
Hudson275.2442.95 CR 12 (Franklin Street) – Hudson
IL 251 north / CR 8 (Lake Bloomington Road) – Kappa
Southern terminus of IL 251
WoodfordEl Paso284.9458.514 US 24 – El Paso, Peoria
Woodford292.9471.422 IL 116 – Peoria, Pontiac
MarshallWenona305.6491.835 IL 17 – Lacon, Wenona
LaSalleLostant312.2502.441 IL 18 – Henry, Streator
322.3518.751 IL 71 – Hennepin, Oglesby
323.0519.852 IL 251 – Peru, LaSalle
Illinois River326.5525.5Abraham Lincoln Memorial Bridge
La Salle327.3526.757 US 6 – LaSalle, Peru, Ottawa
329.6530.459 I-80 – LaSalle, Peru, Chicago, Des MoinesSigned as exits 59A (east) and 59B (west); I-80 exit 79
Troy Grove336.8542.066 US 52 – Troy Grove
Mendota342.7551.572 US 34 – Mendota, Earlville
LeePaw Paw353.1568.382Paw Paw
357.9576.087 US 30 – Sterling, Rock Falls, Aurora

I-88 Toll / IL 110 (CKC) (Ronald Reagan Memorial Tollway) – Moline, Rock Island, Chicago
Signed as exits 97A (east) and 97B (west); I-88 exit 78
370.1595.699 IL 38 / Lincoln Highway – DeKalb, Rochelle
375.1603.7104 IL 64 – Sycamore, Oregon
Monroe Center381.6614.1111 IL 72 – Genoa, Byron
Winnebago386.1621.4115Baxter Road
US 20 west – Freeport, Rockford
Southern end of US 20 concurrency
Cherry Valley392.7632.0122A
US 20 east – Belvidere
Northern end of US 20 concurrency
392.7632.0122BHarrison Avenue

I-90 Toll east (Jane Addams Memorial Tollway) – Chicago
Southern end of I-90 concurrency; I-39/US 51 uses I-90's exit numbers from here north; exit 17 on I-90
US 20 Bus. (State Street)
Last free exit northbound
398.4641.212Riverside BoulevardToll on northbound exit and southbound entrance
Machesney Park401.9646.89 IL 173 (West Lane Road) – Machesney ParkToll on northbound exit and southbound entrance
Rockton407.3655.5South Beloit Toll Plaza
South Beloit408.1656.83 CR 9 (Rockton Road)Last free exit southbound

I-39 north / I-90 west – Madison

IL 75 east (Manchester Road)
Northern end of I-39/I-90 concurrency; southern end of IL 75 concurrency

IL 75 west (Gardner Street) / IL 251 south (North 2nd Street) – Freeport, Rockford
Northern end of IL 75 concurrency; northern terminus of IL 251
US 51 north (Dearborn Street) – Beloit
Continuation into Wisconsin
1.000 mi = 1.609 km; 1.000 km = 0.621 mi


  1. ^ a b Illinois Technology Transfer Center (2007). "T2 GIS Data". Illinois Department of Transportation. Retrieved November 8, 2007.
  2. ^ "Illinois Supplemental Freeway system proposal" (PDF). Retrieved February 17, 2015.
  3. ^ Google (March 19, 2017). "Overview Map of US 51" (Map). Google Maps. Google. Retrieved March 19, 2017.

External links

U.S. Route 51
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