The Duff Building is a commercial structure located at 118 West Exchange Street in Owosso, Michigan.

[2] By 1912, Duff moved his store to another location, and sold the Exchange Street building to Willis E. Hall and George W. Detwiler.

Detwiler took over as sole owner, ond over the next two decades the building housed the Detwiler grocery, the jewelry firm of D.H. Wen and Company, optometrist George B. Gilbert, the Knapp and Smith Undertaking firm, the Owosso Meat Market, and Telfers Market.

The facade is designed in an Italianate style, with one storefront containing a recessed doorway, wide windows with kick panels below, and brick side piers.

The second floor contains two paired, one-over-one, double hung sash windows set in bowed-arch brick openings.