Illinois Route 161 is an east–west highway with its western terminus at Illinois Route 157

Illinois Route 157

Illinois Route 157 is a north–south highway in southwestern Illinois. Its southern terminus is at Illinois Route 3 at Cahokia, Illinois and its northern terminus at Illinois Route 140 in Hamel. This is a distance of .- Route description :...

 in Fairview Heights

Fairview Heights, Illinois

Fairview Heights is a city in St. Clair County, Illinois, United States. The population was 17,078 at the 2010 census. Fairview Heights is a dominant shopping center for Southwestern Illinois and includes numerous shopping plazas and the St...

 and its official eastern terminus at Illinois Route 37

Illinois Route 37

Illinois Route 37, or Illinois 37, is a north–south route in southern Illinois. It is in length. Originally connecting Effingham to Cairo, it was a heavily-traveled highway before Interstate 57 was opened. That Interstate, which lies very close to most of Illinois 37 , supplanted it as a...

 near Kell

Kell, Illinois

Kell is a village in Marion County, Illinois, United States. The population was 231 at the 2000 census.-Geography:Kell is located at .According to the United States Census Bureau, the village has a total area of , all of it land....

. This is an official distance of 67.24 miles (108.21 km).

The road continues, as various county routes, eastbound beyond Illinois 37 to Allendale

Allendale, Illinois

Allendale is a village in Wabash Precinct, Wabash County, Illinois. The population was 528 at the 2000 census.- History :The original location of Allendale was Timberville, South of the current location. When the railroad was to come through the region, the town was moved to its current location...

 at Illinois Route 1

Illinois Route 1

Illinois Route 1 is a state highway in the U.S. state of Illinois. Running parallel to the Indiana border, it is also the longest state road, starting on the south side of Chicago as Halsted Street at the intersection with 95th Street, south to a free ferry crossing to Kentucky at Cave-In-Rock on...

.

Route description

Illinois 161 runs along portions of what once was U.S. Route 50

U.S. Route 50

U.S. Route 50 is a major east–west route of the U.S. Highway system, stretching just over from Ocean City, Maryland on the Atlantic Ocean to West Sacramento, California. Until 1972, when it was replaced by Interstate Highways west of the Sacramento area, it extended to San Francisco, near...

 west of Scott Air Force Base. East of Belleville, it becomes a rural, two-lane surface road. Inside the Centralia city limits, Illinois 161 is coupled into east bound Noleman Street and west bound McCord Street.

Cities

Note: Bold indicates city on official designation area.

• Fairview Heights
  Fairview Heights, Illinois
  Fairview Heights is a city in St. Clair County, Illinois, United States. The population was 17,078 at the 2010 census. Fairview Heights is a dominant shopping center for Southwestern Illinois and includes numerous shopping plazas and the St...
  
  
• Belleville
  Belleville, Illinois
  Belleville is a city in St. Clair County, Illinois, United States. As of the 2010 census, the city has a population of 44,478. It is the eighth-most populated city outside of the Chicago Metropolitan Area and the most populated city south of Springfield in the state of Illinois. It is the county...
  
  
• Swansea
  Swansea, Illinois
  Swansea is a village in St. Clair County, Illinois, United States. The population was 10,579 at the 2000 census.-History:In the late 19th century the area that is now Swansea was a mix of farming and commerce. It was home to underground coal mines, foundries, brickyards, and the Gundlach Drill...
  
  
• Scott AFB
  Scott Air Force Base
  Scott Air Force Base is a base of the United States Air Force in St. Clair County, Illinois, near Belleville.-Overview:The base is named after Corporal Frank S. Scott, the first enlisted person to be killed in an aviation crash...
  
  
• Mascoutah
  Mascoutah, Illinois
  Mascoutah is a small town in St. Clair County, Illinois, United States. The population was 7,483 at the 2010 census.-Geography:Mascoutah is located at ....
  
  
• New Baden
  New Baden, Illinois
  New Baden is a village in Clinton County, Illinois, United States. The population was 3,349 at the 2010 census.-Geography:New Baden is located at ....
  
  
• Albers
  Albers, Illinois
  Albers is a village in Clinton County, Illinois, United States. The population was 878 at the 2000 census.-Geography:Albers is located at ....
  
  
• Germantown
  Germantown, Illinois
  Germantown is a village in Clinton County, Illinois, United States. The population was 1,118 at the 2000 census.-History:The village of Germantown was established in 1833. Formerly known as Hanover, Germantown is said to be one of the first true German settlements in Illinois...
  
  
• Bartelso
  Bartelso, Illinois
  Bartelso is a village in Clinton County, Illinois, United States. The population was 593 at the 2000 census.-Geography:Bartelso is located at ....
  
  
• Hoffman
  Hoffman, Illinois
  Hoffman is a village in Clinton County, Illinois, United States. The population was 460 at the 2000 census.-Geography:Hoffman is located at ....
  
  
• Centralia
  Centralia, Illinois
  Centralia is a town located in Marion, Washington, Clinton, and Jefferson Counties in the U.S. state of Illinois. The population was 13,032 at the 2010 census. The town was founded because it was the point where the two original branches of the Illinois Central Railroad, built in 1853, converged....
  
  
• Kell
  Kell, Illinois
  Kell is a village in Marion County, Illinois, United States. The population was 231 at the 2000 census.-Geography:Kell is located at .According to the United States Census Bureau, the village has a total area of , all of it land....
  
  
• Cisne
  Cisne, Illinois
  Cisne is a village in Wayne County, Illinois, United States. The population was 673 at the 2000 census. Cisne was named in 1870 in honor of Levi Cisne on the suggestion of Charles A. Beecher, who was influential in building the railroad and the station around which the village of Cisne...
  
  
• Mt. Erie
  Mount Erie, Illinois
  Mount Erie is a village in Wayne County, Illinois, United States. The population was 105 at the 2000 census.-Geography:Mount Erie is located at ....
  
  
• W. Salem
  West Salem, Illinois
  West Salem is a village in Edwards County, Illinois, United States. The population was 1,001 at the 2000 census.-Earthquake:West Salem is within the Wabash Valley seismic zone. On April 18, 2008 at 09:36:56 UTC a moderate earthquake of 5.2 magnitude was centered near the village...
  
  
• Lancaster
  Lancaster, Illinois
  Lancaster is an unincorporated community in Wabash County, Illinois, United States. Lancaster is located 9 miles west of Allendale and 12 miles northwest of Mt. Carmel....
  
  
• Allendale
  Allendale, Illinois
  Allendale is a village in Wabash Precinct, Wabash County, Illinois. The population was 528 at the 2000 census.- History :The original location of Allendale was Timberville, South of the current location. When the railroad was to come through the region, the town was moved to its current location...
  
  

History

SBI Route 161 originally ran from Belleville to Carlyle

Carlyle, Illinois

Carlyle is a city in Clinton County, Illinois, United States. The population was 3,406 at the 2000 census. It is the county seat of Clinton County.Carlyle is located approximately 50 miles east of St...

; in 1941 it was rerouted from Carlyle to Illinois 37 at its current eastern end. In 1964 it was extended west to Fairview Heights.