Robert Horace Lounsberry (June 22, 1918 – February 10, 2001) was the Secretary of Agriculture for the state of Iowa from 1972 to 1987, a nationally known farmer advocate during the farming crises of the 1980s, and a powerful figure in the Republican Party at both the state and national level. Lounsberry was active in the Republican Party, serving on the local, county, district and state levels. He was a key player in the Iowa Presidential Caucus, with Presidents Ronald Reagan, George H. Bush, and George W. Bush all holding campaign events at his farm near McCallsburg, Iowa.