U.S. Route 51 in Illinois

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This article is about the section of U.S. Route 51 in Illinois. For the entire route, see U.S. Route 51.

U.S. Route 51 marker

U.S. Route 51
Route information
Maintained by IDOT
Length: 415.95 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

I-57 near Cairo
I-64 near Richview
I-70 at Vandalia
I-72 at Decatur
I-39 / I-55 / I-74 at Bloomington/Normal
I-80 at La Salle
I-88 at Rochelle
I-90 at Rockford

I-39 / I-90 at South Beloit
North end: US 51 at the Wisconsin state line in South Beloit
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[edit]

U.S. Route 51 enters Illinois from Kentucky at the town of Cairo. The route heads northbound to a village near Cairo called Mounds, and begins to overlap I-57, following it for 24 miles (39 km) to Dongola, before splitting and heading north. The route remains two lanes 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 town. US 51 leaves I-72 after eight miles (13 km), and 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 joins I-90, making US 51 of the only toll roads in Illinois that is a U.S. Highway. US 51 exits I-39/I-90 just a mile south of the Wisconsin state line. US 51 follows Illinois Route 75 (IL 75) west to the intersection of IL 251, then turns north through South Beloit to enter Wisconsin.


US 51 was established in Illinois in the 1920s. Over the years, it became a heavily traveled road, often experiencing many accidents, particularly in the northern half of the state. The road gained the reputation "Killer 51". As a result of these impacts, 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 prioritized.[2]

In the 1980s and early 1990s, US 51 was built to Interstate Highway standards between Rockford and BloomingtonNormal on a new alignment. This new road became Interstate 39, and US 51 was re-routed onto the new highway. Additionally, north of Rockford, it was re-routed onto the existing Interstate 90 tollway segment between South Beloit and Cherry Valley. Most of the old alignment became Illinois Route 251.

South of Bloomington–Normal to Decatur, US 51 remained largely on the original alignment and was expanded to an expressway, despite a push to continue building to Interstate Highway standards.[3] Further continuation of the expressway occurred in the 2000s, when the highway was upgraded south to Assumption.


Plans are underway to continue the US 51 expressway south of Assumption to Centralia.[4] An environmental impact statement is currently being prepared. However, construction funding remains elusive.

Major intersections[edit]

County Location mi km Exit Destinations Notes
Alexander Cairo US 51 south / US 60 east / US 62 east – Wickliffe US 51/US 60/US 62 continue into Kentucky
US 60 west / US 62 west – Charleston Northern end of US 60/US 62 concurrency
IL 37 north – Mound City Southern terminus of IL 37
1 I-57 south / IL 3 north – Olive Branch, Memphis Southern end of I-57 concurrency; southern terminus of IL 3
Pulaski   8 Mounds Road
  18 Ullin Road
Union Dongola 24 Dongola Road
25 I-57 north – Chicago Northern end of I-57 concurrency; northbound exit and southbound entrance
Anna IL 146 – Jonesboro, Vienna
Jackson Carbondale IL 13 – Murphysboro, Marion
De Soto IL 149 – Murphysboro, Hurst
Perry Du Quoin IL 14 east – Christopher Western terminus of IL 14
IL 152 west – Pyatts Eastern terminus of IL 152
Sunfield IL 154 – Red Bud, Sesser
Washington Ashley IL 15 west – East St. Louis Western end of IL 15 concurrency
IL 15 east – Mount Vernon Eastern end of IL 15 concurrency
Richview I-64 – St. Louis, Louisville Exit 61 on I-64
Irvington IL 177 west – Belleville Western terminus of IL 177
Marion Centralia IL 161 – New Baden, Kell
Sandoval US 50 west – Carlyle Western end of US 50 concurrency
US 50 east – Salem Eastern end of US 50 concurrency
Fayette Vandalia 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
I-70 – St. Louis, Indianapolis Exit 63 on I-70
Christian Pana IL 16 west Western end of IL 16 concurrency
IL 29 north Southern terminus of IL 29
  IL 16 east Eastern end of IL 16 concurrency
US 51 Bus. north
  IL 48
Harristown 133 I-72 west / US 36 – Springfield, Tuscola Southern end of I-72 concurrency; signed as exits 133A (east) and 133B (south)
Decatur 138 IL 121 – Decatur, Lincoln
I-72 east / US 51 Bus. south – Champaign, Urbana, Decatur
DeWitt Clinton
US 51 Bus. north – Clinton
IL 54
IL 10

US 51 Bus. south – Clinton
McLean Heyworth US 136 – McLean, Rantoul
I-74 east / US 51 Bus. north (Main Street) – Indianapolis, Bloomington
Southern end of I-74 concurrency
  157A I-55 south – St. Louis Southern end of I-55 concurrency
Bloomington 157B I-55 Bus. north (Veterans Parkway) Signed as exit 134B (north) southbound
160 US 150 / IL 9 (Market Street) – Pekin
  163 I-74 west – Peoria Northern end of I-74 concurrency
  164 I-39 north / I-55 north – Chicago Northern end of I-55 concurrency; southern end of I-39 concurrency; southern terminus of I-39
US 51 Bus. south – Bloomington, Normal
Hudson 5 Hudson
  8 IL 251 (Lake Bloomington Road)
Woodford El Paso 14 US 24 – El Paso, Peoria
Woodford 22 IL 116 – Peoria, Pontiac
Minonk 27 Minonk
Marshall Wenona 35 IL 17 – Lacon, Wenona
LaSalle Lostant 41 IL 18 – Henry, Streator
Tonica 48 Tonica
  51 IL 71 – Hennepin, Oglesby
  52 IL 251 – Peru, LaSalle
Oglesby 54 Oglesby
Illinois River Abraham Lincoln Memorial Bridge
La Salle 57 US 6 – LaSalle, Peru, Ottawa
  59 I-80 – LaSalle, Peru, Chicago, Des Moines Signed as exits 59A (east) and 59B (west)
Troy Grove 66 US 52 – Troy Grove
Mendota 72 US 34 – Mendota, Earlville
Lee Paw Paw 82 Paw Paw
  87 US 30 – Sterling, Rock Falls, Aurora
Steward 93 Steward
Ogle Rochelle 97 I-88 / IL 110 (Ronald Reagan Memorial Tollway) – Moline, Rock Island, Chicago Signed as exits 97A (east) and 97B (west)
99 IL 38 – DeKalb, Rochelle
  104 IL 64 – Sycamore, Oregon
Monroe Center 111 IL 72 – Genoa, Byron
Winnebago   115 Baxter Road
Rockford US 20 west – Freeport, Rockford Southern end of US 20 concurrency, I-39/US 51 southbound exits US 20 via exit 97
Cherry Valley 122A US 20 east – Belvidere Northern end of US 20 concurrency
122B Harrison Avenue
17 I-90 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
Rockford 16
US 20 Bus. (State Street)
Last free exit northbound
12 Riverside Boulevard Toll on northbound exit and southbound entrance
Machesney Park 9 IL 173 (West Lane Road) Toll on northbound exit and southbound entrance
Rockton South Beloit Toll Plaza
South Beloit 3 Rockton Road (CR 9) Last free exit southbound
1 I-39 north / I-90 west / IL 75 east – South Beloit, Madison Northern end of I-39/I-90 concurrency; eastern end of IL 75 concurrency
IL 75 west / IL 251 south – Freeport, Rockford Western end of IL 75 concurrency; northern terminus of IL 251
US 51 north – 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. ^ Wills, Bill. "Decatur trying to block road plan". The Pantagraph. Retrieved February 17, 2015. 
  4. ^ "US 51 Environmental Impact Statement". Illinois Department of Transportation. Retrieved February 17, 2015. 

External links[edit]

U.S. Route 51
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