The papers of John N. Calhoun are comprised of fifteen boxes of manuscripts measuring eight linear feet and dating from 1923 to 1954. The collection is divided into five series: 1) General subject files; 2) Campaign for U.S. Congress, 1936; 3) Legal materials; 4) World War II service; and 5) Post World War II political career. The first series deals with his education, early professional life, and legislative career. The subject files primarily relate to legislative issues such as road legislation, oleo margarine tax, or tuberculin testing. Extensive correspondence files include letters from William S. Beardsley, Don L. Berry, Robert D. Blue, Lester J. Dickinson, Edward C. Etcher, Fred C. Gilchrist, Clyde L. Herring, Bourke B. Hickenlooper, Nelson G. Kraschel, J. C. Lewis, Hugh W. Lundy, Paul H. McCoid, Thomas E. Martin, Richard L. Murphy, Addison M. Parker, Wiley Rutledge, Harrison E. Spangler, Lloyd Thurston, Dan W. Turner, George A. Wilson.

The next grouping relates to his campaign for a US Senate seat in 1936. His nomination papers, campaign expenses, schedules, advertising, and party correspondence are some of the files in this section. Court cases and legal briefs make up the legal materials division. His World War II service is documented with photos, family correspondence, and military records. The final series titled Post World War II political career consists of material from his 1948 campaign for the US Senate and other political campaigns in which he was involved.