Chicago Drive, largely signed as M-121, is a combination state trunkline highway and municipal street running from 8th Street in Holland to the intersection of Cesar E Chavez (formerly known as Grandville) and Clyde Park avenues at the border of Grand Rapids and Wyoming, approximately 23.5 miles (37.8 km) in length.

The highway continues to the northeast out of town through suburban residential areas to Jenison, where once again Chicago Drive is bordered by commercial properties.

In Wyoming from north of M-11 (28th Street) to Burlingame Avenue, Chicago Drive run through a mostly industrial area with few commercial properties.

Northeast of about Byron Center Avenue, Chicago Drive carries Business Spur I-196 (BS I-196).

At the corner with Cesar E Chavez (formerly known as Grandville) and Clyde Park avenues, Chicago Drive and BS I-196 ends.

As a part of these maintenance responsibilities, the department tracks the volume of traffic that uses the roadways under its jurisdiction.

[5] None of M-121 has been listed on the National Highway System,[6] a network of roads important to the country's economy, defense, and mobility.

[10][11] This Flint-area trunkline provided access to Bishop International Airport from both of the I-69 and I-75/US 23 freeways until it was retired in 2003.