Michigan Highway 120 is a fairly short route in west-central Michigan, extending northeasterly out of Muskegon. The southwestern end occurs at a unique at-grade interchange with the Business Route for US Route 31, on the north side of Muskegon. Michigan Highway 120 sets out northeasterly from there, encountering an interchange with the main freeway alignment of US Route 31. After passing through Twin Lake and Holton, it turns straight northerly, intersection Michigan Highway 82 near Fremont. Seven miles north of that junction, Michigan Highway 120 ends at Michigan Highway 20 in Hesperia. I don't know if Michigan Highway 120 was named after Michigan Highway 20, in the stylings of the Interstate Highway System's numbering scheme, or if the similarity of the two routes' numbers is a complete coincidence.
My photo of signage for Michigan Highway 120 comes from the northbound offramp from US Route 31's freeway portion. An interchange alongside Muskegon provides access from US Route 31 and Michigan Highway 120. The signage depicted is a guide assembly facing south for the sake of detailing the options to travelers heading north on the offramp from US Route 31 northbound. This photo was snapped in March 2018 on the way to Traverse City.