This collection is arranged into two subgroups, Personal Papers and Professional Papers.

Personal Papers (1936-1970) contain biographical materials, correspondence, and legal records. Biographical materials include obituaries and a writing on Malcolm Mackay Sr. Correspondence pertains to non-business matters, and includes correspondents such as Carl Anderson, Prince “Red” Hodgson Gordon, Malcolm “Bud” Mackay, Mary Ellen Wang, and others. Legal records mostly pertain to family Trusts, Estates, and Wills.

Professional Papers (1935-1971) include ephemera, which contain various certificates and nominations; general correspondence, organized alphabetically by person, organization, or subject, depending on original order; financial records; legal records, including agreements; minutes, including the Appropriations Sub-Committee of the University System and the Montana Stockgrowers Association; organizational materials, including bylaws, constitutions, and resolutions of various organizations; published materials; press releases and radio broadcast transcripts; reports; speeches, discussing various state issues like education, financing State services, and the reorganization of Montana State Government; subject files, which primarily refer to House Bills, Senate Bills, legislative committees, State issues, or associations; and miscellaneous writings.