# Illinois Route 121

Illinois Route 121 (IL 121) is a 109.48-mile-long (176.19 km) major state highway in the central part of the U.S. state of Illinois. Although it travels from northwest to southeast, it is marked as a north–south highway. It travels from IL 130 in Greenup (very near U.S. Route 40) to Interstate 55 (I-55) in Lincoln at the interchange of I-55 and IL 10.

## Route description

IL 121 travels north from Greenup near I-70. While traveling northwest, IL 121 travels through Toledo and has an interchange with I-57 in Mattoon.
From there, it travels northwest into the city limits of Decatur but largely goes around downtown using 22nd Street and Pershing Road. On the northwest side of Decatur, IL 121 intersects with the concurrent I-72 and US 51.
IL 121 continues further northwest into Lincoln, where it has a concurrency with IL 10 through Lincoln as Keokuk Street and Woodlawn Road before terminating at I-55 just south of I-155. IL 10 continues west on the same road.

## History

State Bond Issue (SBI) Route 121 formerly traveled from Peoria to the Indiana state line east of Chrisman. When US 36 was established in the late 1920s, IL 121 was dropped east of Decatur. In March 1937, IL 121 replaced then IL 131 and IL 132 south of Decatur to Greenup.
In 1993, I-155 north of Lincoln was completed. IL 121 was then dropped from this stretch of freeway.
IL 121 had a business route through Decatur until about 1980 along Main Street and Water Street. This was replaced by US 51 Business.

## Major intersections

| County | Location | mi | km | Destinations | Notes |
| Cumberland | Greenup | 0.0 | 0.0 | IL 130 | |
| Cumberland | ​ | 19.0 | 30.6 | US 45 south | South end of US 45 concurrency |
| Coles | Mattoon | 23.6 | 38.0 | I-57 – Effingham, Champaign | I-57 exit 184 |
| Coles | Mattoon | 27.4 | 44.1 | IL 16 east – Charleston | South end of IL 16 concurrency |
| Coles | Mattoon | 27.4 | 44.1 | IL 16 west – Shelbyville | North end of IL 16 concurrency |
| Coles | Mattoon | 28.0 | 45.1 | US 45 north – Arcola | North end of US 45 concurrency |
| Moultrie | Sullivan | 44.4 | 71.5 | IL 32 south – Effingham | South end of IL 32 concurrency |
| Moultrie | ​ | 45.8 | 73.7 | IL 32 north – Lovington | North end of IL 32 concurrency |
| Moultrie | Dalton City | 58.8 | 94.6 | IL 128 south – Shelbyville | |
| Macon | Decatur | 67.3 | 108.3 | US 36 east – Tuscola | South end of US 36 concurrency |
| Macon | Decatur | 70.4 | 113.3 | US 36 west / IL 105 west – Springfield | North end of US 36 concurrency; south end of IL 105 concurrency |
| Macon | Decatur | 70.6 | 113.6 | IL 105 east – Monticello | North end of IL 105 concurrency |
| Macon | Decatur | 72.7 | 117.0 | IL 48 north – Argenta | South end of IL 48 concurrency |
| Macon | Decatur | 74.3 | 119.6 | US 51 Bus. north (Water Street) – Bloomington, Clinton | One-way pair |
| Macon | Decatur | 74.4 | 119.7 | US 51 Bus. south (Main Street) – Macon, Pana | One-way pair |
| Macon | Decatur | 75.3 | 121.2 | IL 48 south – Taylorville | North end of IL 48 concurrency |
| Macon | Decatur | 77.5 | 124.7 | I-72 / US 51 – Springfield, Pana, Champaign, Bloomington | I-72 exit 138 |
| Logan | Mt. Pulaski | 94.3 | 151.8 | To IL 54 – Clinton, Springfield | |
| Logan | Lincoln | 105.5 | 169.8 | IL 10 east – Clinton | South end of IL 10 concurrency |
| Logan | Lincoln | 105.9 | 170.4 | I-55 BL north (Kickapoo Street) / Historic US 66 east | 1930-1940 Historic US 66 |
| Logan | Lincoln | 106.1 | 170.8 | I-55 BL south (Logan Street) / Historic US 66 west | 1930-1940 Historic US 66 |
| Logan | Lincoln | 107.6 | 173.2 | Historic US 66 (Lincoln Parkway) | |
| Logan | Lincoln | 109.48 | 176.19 | I-55 to I-155 north – Bloomington, Springfield, Peoria IL 10 west – Mason City | Northern terminus; north end of IL 10 concurrency; I-55 exit 126 |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi Concurrency terminus ||||||