In Miller City the road has an at-grade crossing with a Norfolk Southern Railroad track.

The highway enters Holgate and the roadway curves northeast, passing through residential properties.

The road crosses a set of CSX Railroad tracks, before entering downtown Holgate.

After turning northeast the highway leaves downtown and passes through residential properties on the north side of Holgate.

In downtown Napoleon, the highway passes through commercial type business, before turning southwest onto Clinton Street.

At a five-way intersection SR 108 turns northwest, onto Scott Street, leaving downtown Napoleon.

At a traffic light with Lagrange Street the route curves due north, passing through commercial businesses.

The two routes head west passing through farmland, before SR 108 turns due north leaving the concurrency.

SR 108 heads north passing farmland, before ending at the Michigan state line, south of Morenci.

[3][18] In March 2020, a bill was signed into law naming SR 108 through Henry County the Alene Duerk Memorial Highway, named for Alene Duerk, the first female admiral in the U.S. Navy who grew up in Holgate.