Fonds comprises Ronald St. John Macdonald's records regarding his personal, academic, and professional activities as a jurist, judge, and professor. Records include those related to Macdonald's involvement with Osgoode Hall, University of Western Ontario, University of Toronto, Dalhousie University, the European Court of Human Rights, the Hague, Peking University, World Academy of Arts and Science, Canadian Council of International Law, United Nations, Institute of International Law, African Society of International Law, British Institute of International Law, Canadian Institute of International Law, International Law Association, and others. Records types include correspondence; meeting minutes and agendas; research materials; photographs; newsletters; newspaper clippings; manuscripts; and off-prints.

Series comprises correspondence regarding Macdonald's professional and academic involvement with institutions including Osgoode Hall, University of Western Ontario, University of Toronto, Dalhousie University, the European Court of Human Rights, the Hague, Peking University, World Academy of Arts and Science, Canadian Council of International Law, United Nations, Institute of International Law, African Society of International Law, British Institute of International Law, Canadian Institute of International Law, International Law Association, and others. Series also contains correspondence between Ronald St. John Macdonald and individuals including Joseph Philippe Pierre Yves Elliott Trudeau, Paul E. Martin, Jean Chrétien, Elisabeth Mann Borgese, Wang Tieya, A. Donat Pharand, and others.

Subseries contains Ronald St. John Macdonald's correspondence with different individuals and organizations, including A. Donat Pharand, J. Alan Beesley, Bozidar Bokatic, Charles B. Bourne, Donald A. Kerr, Donald McInnes, Douglas M. Johnston, Edgar Gold, Elisabeth Mann Borgese, Gerald L. Morris, Ivan Leigh Head, John P. Humphrey, John King Gamble Jr., Leslie C. Green, Maxwell Cohen, Wang Tieya, the Canadian Department of External Affairs, the Council of Europe, and others, regarding a wide range of subjects.