Illinois Route 251

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Illinois Route 251

IL 251 highlighted in red
Route information
Maintained by IDOT
Length135.32 mi[1] (217.78 km)
ExistedEarly 1970s[2]–present
Major junctions
South end I-39 / US 51 / CR 8 in Hudson
Major intersections
North end US 51 / IL 75 in South Beloit
CountryUnited States
CountiesMcLean, Woodford, Marshall, LaSalle, Lee, Ogle, Winnebago
Highway system
IL 250 I-255

Illinois Route 251 is a north–south state highway that runs on the former alignment of U.S. Route 51 before Interstate 39 was built in north central Illinois. It runs from U.S. 51 at the border with Wisconsin to I-39 and U.S. 51 south of Kappa. Illinois 251 is 135.32 miles (217.78 km) long.[1]

Route description

Aerial view of I-39 (left) and IL 251 (right) in Minonk

Illinois 251 runs parallel to Interstate 39 and U.S. 51 for most of the length of I-39 in Illinois. Like Illinois Route 351, it can be considered a spur, loop or alternate of its parent route, U.S. 51. Illinois 251 terminates about 8 mi (13 km) north of the southern terminus of I-39.

The road parallels the east bank of the Rock River through Rockford, where the highway goes north on Eleventh Street, west on Harrison, north on Kishwaukee, west on Walnut then split between northbound Third and southbound Second through downtown Rockford. After downtown, both directions take the southbound lanes' Second Street name as a divided urban expressway (also badged as Martin Luther King Jr. Memorial Drive) for a couple of miles north of downtown Rockford. It stays Second Street through Loves Park, Machesney Park and Roscoe until its north endpoint at US 51 and Illinois 75 in South Beloit


Illinois 251 was established in 1982 when first segment of I-39 opened between Rockford and Bloomington. In 1992, the final segment of I-39 opened north of Bloomington. The remaining stretch of former U.S. 51 became Illinois 251.[3] The initial designation of I-39 was U.S. Route 51 until 1992.

Major intersections

McLean0.00.0 I-39 / US 51 – Bloomington–Normal, RockfordSouthern terminus; I-39 exit 8
WoodfordEl Paso7.111.4 US 24 (West Main Street)
IL 116 west
South end of IL 116 overlap
IL 116 east
North end of IL 116 overlap
IL 17 west
South end of IL 17 overlap
IL 17 east (Elm Street)
North end of IL 17 overlap
LaSalle34.655.7 IL 18 (North 13th Road)
Tonica41.767.1 CR 54 (Ray Richardson Road, Ed Lambert Road)
IL 71 / IL 351 north
45.673.4 I-39 / US 51 – Bloomington–Normal, RockfordI-39 exit 52
Illinois River49.679.8Peru Bridge
Peru49.880.1 US 6 – LaSalle, Spring ValleyInterchange
52.584.5 I-80 – Moline, Rock Island, JolietI-80 exit 75
55.789.6 CR 33 (North 33rd Road)
US 52 east (North 37th Road)
South end of US 52 overlap
Mendota65.1104.8 US 34 (Washington Street, Walter Payton Memorial Highway)
US 52 west
North end of US 52 overlap
Lee81.6131.3 US 30

I-88 Toll / IL 110 (CKC) (Ronald Reagan Memorial Tollway) – Chicago, Moline, Rock Island
I-88 exit 76
IL 38 west / Lincoln Highway (Lincoln Avenue)
South end of IL 38 overlap
IL 38 east / Lincoln Highway (May Mart Drive)
North end of IL 38 overlap
99.0159.3 IL 64
Davis Junction105.8170.3 IL 72 (Chicago Avenue)
WinnebagoRockford114.0183.5 US 20 (Rockford Bypass, Ulysses S. Grant Memorial Highway) – Freeport, BelvidereInterchange
US 20 Bus. (1st Avenue, Jefferson Street)
118.7191.0Whitman Street BridgeInterchange
120.1193.3Auburn Street, Spring Creek RoadInterchange
120.6194.1Forest Hills RoadNorthbound exit and southbound entrance
Machesney Park125.7202.3
IL 173 east (West Lane Road)
Roscoe132.8213.7 CR 76 (Prairie Hill Road)
Rockton133.8215.3 CR 9 (Rockton Road)Interchange
South Beloit135.32217.78 US 51 / IL 75 (Gardner Street)Northern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi


  1. ^ a b Illinois Technology Transfer Center (2006). "T2 GIS Data". Retrieved 2007-11-08.
  2. ^ Carlson, Rich. Illinois Highways Page: Routes 200 thru end. Last updated April 15, 2005. Retrieved May 12, 2006.
  3. ^ AARoads. Interstate 39 @
  4. ^ Google (March 12, 2017). "Overview Map of IL 251" (Map). Google Maps. Google. Retrieved March 12, 2017.

External links