The Charles J. Thompson House, now known as the Mansion Museum, is a historic building located in Forest City, Iowa, United States.

The house was built for a local banker named Charles J. Thompson.

The large portico with fluted columns in the Corinthian order and pilasters is the central feature of the house.

[2] The house was acquired by the Winnebago Historical Society, which operates it as a local history museum.

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