MN 121 runs between Interstate Highway 35W in Richfield and Lyndale Avenue South (CSAH 22) in Minneapolis where it intersects West 58th Street.

MN 121 serves as a freeway connector stub on the Minneapolis / Richfield boundary line.

When traveling on I-35W northbound in Richfield, MN 121 is accessed by the "Highway 62 west / 58th Street" exit.

Before I-35W was completed to downtown Minneapolis, old U.S. Highway 65 briefly took this stub (present day MN 121) to rejoin its old alignment on Lyndale Avenue South.

The first alignment of MN 121 on France Avenue South was signed in 1935 between 50th Street northbound to Excelsior Boulevard.