Claim: Plagmann Round Barn was built in 1912 as a cattle barn by Charles and Richard Plagmann, and this round barn (a historic barn design that could be octagonal, polygonal, or circular in plan)  measured 100 feet (40 m) in diameter.
Evidence: The Plagmann Round Barn is an historic building located near Conroy in rural Iowa County, Iowa, United States. It was built in 1912 as a cattle barn by Charles and Richard Plagmann. The building is a true round barn that measures 100 feet (30 m) in diameter. A round barn is a historic barn design that could be octagonal, polygonal, or circular in plan. 1912 Charles & Richard Plagmann