the worlds largest round barn is in marshfield Wisconsin at the fairgrounds where the fair is held. i would know because i live there. it is not in wausa.
University of Wisconsin Dairy Barn was created in 1897.
Neff Round Barn was created in 1910.
Spotts Round Barn was created in 1914.
Kelly Round Barn was created in 1893.
Eckle Round Barn was created in 1928.
Plagmann Round Barn was created in 1912.
Clark Round Barn was created in 1908.
Holtkamp Round Barn was created in 1918.
Ryan Round Barn was created in 1910.
Hamilton Round Barn was created in 1911.
Bates Round Barn was created in 1928.
Young Round Barn was created in 1914.