Most of the route is a rural two-lane highway and passes through both farmland and residential properties.

After the tracks the road makes a turn heading northwest, onto Elwood Avenue, passing through residential properties.

SR 31 leaves Marysville, heading towards the northwest, passing through farmland, as a two-lane highway.

The highway has an at-grade crossing CSX railroad tracks, before entering downtown Mt.

As the road enters Kenton it is locally known as Main Street and has a T-intersection with SR 292.

The road passes through industrial properties, before crossing CSX railroad tracks.

The highway has an intersection with SR 309, on the southeast corner of the Hardin Country Court House.

The road passes on the east side of the court house, before having an intersection with SR 67.

[15][16] In 1951 the concurrency with US 68 was removed, making Kenton the northern terminus of SR 31.