Correspondence, memoranda, speeches, reports, articles, political and subject files, legal records, biographical material, newspaper clippings, scrapbooks, printed matter, photographs, and other papers relating primarily to Lenroot's political campaigns and membership in the Wisconsin state legislature, the U.S. House of Representatives, and the U.S. Senate; role in the Wisconsin Progressive movement; association with Robert M. La Follette; and relationship with national political leaders. Includes holograph notebooks concerning his congressional career and a typescript draft of his unpublished memoirs (1948). Papers of the Clough and Lenroot families include correspondence, genealogical material, and diaries and writings of Lenroot's wife, Clara Clough Lenroot. Correspondents include Calvin Coolidge, Charles Henry Crownhart, William H. Dougherty, Herman Lewis Ekern, Guy Despard Goff, John J. Hannan, William Hard, Warren G. Harding, Herbert Hoover, Walter Jodok Kohler, Robert M. La Follette, Henry Cabot Lodge, Gifford Pinchot, Alfred Thomas Rogers, and Mark Sullivan.