The 55 foot (16.8 m) diameter Gerald Harbach Round Barn stands upon a poured concrete foundation near the unincorporated community of Eleroy in Stephenson County, Illinois, United States.

In addition, there are beams nailed diagonally between the studs in the loft to brace the building against strong winds.

The animal entrance, in the southeast quadrant of the barn, has also been sealed since the building is primarily used for storage.

It is not entirely unique; its cupola and roof make it very similar to the Fehr Round Barn.

The building was added to the U.S. National Register of Historic Places on February 23, 1984 as part of a Multiple Property Submission.