How Many Round Barns?
A computer search of the National Register of Historic Places discloses the following inventory of round/polygonal barns (by state). Please note that these are only approximations since not all “round” barns are listed in the Register due to not having been nominated or being ineligible because of their deteriorated state. For example, in SD there were originally 44 round/polygonal/centric barns of which 36 existed in 1995, but only seven were on the Register.