• Addams, Jane, 1924, October 14
• Allen, Robert S., [1922, circa August] (“important campaign notes”)
• Baldwin, Roger, 1924, August
• Beedle, George E., scattered
• Blaine, John J., 1928, November
• Browne, Edward E., 1924, August
• Commons, John R., 1924, August
• Cooper, Henry Allen, 1924, September
• Dykstra, Clarence A., 1940s
• Evjue, William T., 1917-1950s (scattered)
• Frankfurter, Felix, 1924, October 10
• Frear, James A., 1935, February
• Heil, Julius P., 1940, July
• Hillquit, Morris, 1924, September - October
• Huber, Henry A., 1924
• Johnston, William H., 1924
• Kearl, Bryant, 1948, May 7 (regarding finances of 1924 campaign)
• King, Judson, 1917-1950s
• La Follette, Belle Case, 1928, January 10
• La Follette, Philip F., scattered
• La Follette, Robert M., Sr., 1920, 1924
• La Follette, Robert M., Jr., scattered, but especially 1924
• Levitan, Solomon, 1924, October
• Manly, Basil, 1920, October 8 (Memo regarding Chicago Conference of Progressives); 1924
• Nelson, John M., 1924
• Norris, George W., 1940, September 20
• Olbrich, Michael B., 1920-1921
• Pedrick, Samuel M., 1949-1950
• Rawleigh, W. T., 1924
• Renk, Wilbur N., 1954, January 27
• Rennebohm, Oscar, 1954, November 24
• Reynolds, John W., 1926, October 8
• Rogers, Alfred T., 1921, 1924
• Rubin, Morris H., 1950s
• Sauthoff, Harry, 1924
• Schneider, George J., 1924, September
• Sensenbrenner, Frank J., 1940s
• Sigman, Samuel, 1924, September; 1928
• Thompson, Carl, scattered
• Viereck, George Sylvester, 1924
• Walsh, Frank P., 1924, August 27, September 12
• Wheeler, Burton K., letters about Wheeler appear throughout the 1924 campaign correspondence
• White, William Allen, 1924, September 3
• Witte, Edwin E., scattered--fairly extensive for 1920s and 1930s: see especially 1924; 1929, May 16; 1932, January 31; 1936, April 1
• Zimmerman, Fred R., 1926