The Plummer Building in Rochester, Minnesota is one of the many architecturally significant buildings on the Mayo Clinic campus. This new "Mayo Clinic" building, opened in 1927, added much needed space to the ever expanding Mayo practice. The architect of record is Ellerbe & Co., now Ellerbe Becket. It was the third building designed by the firm for the Mayo Clinic. The Mayo Clinic Buildings were listed on the U.S. National Register of Historic Places in 1969, and the Plummer Building was further designated as U.S.