The Joseph P. Mentzer House is a historic building located in Marion, Iowa, United States.

An Ohio native, Mentzer made his fortune as a merchant and as a banker in Marion.

[2] After his business partnership dissolved in 1865, he turned his attention to a 170-acre (69 ha) farm he bought on the edge of town.

It features a mansard roof with bracketed eaves and a single-story rear wing.

This article about a property in Linn County, Iowa on the National Register of Historic Places is a stub.