The Erza McKenzie Round Barn is a historic building located near Hazleton in rural Buchanan County, Iowa, United States. It was built in 1922 by Erza McKenzie for a dairy barn.[2] The building is a true round barn that measures 70 feet (21 m) in diameter.[3] The barn is constructed of clay tile and features small cupolas on the west, southwest and south sides of the structure. The building features a two-pitch roof and a central silo.[3] It has been listed on the National Register of Historic Places since 1986.[1]