The papers of Harold LeClair Ickes (1874-1952) span the years 1815-1969, with the bulk of the material concentrated in the period 1933-1951. Almost all aspects of Ickes's career are illuminated in the papers through letters to friends and critics, official correspondence while he was secretary of the interior, his diary, unpublished and published memoirs and autobiographical sketches, and speeches and statements. Ickes's diary includes observations on affairs of state and prominent public figures. Although the collection includes little family correspondence , Ickes's memoirs in the Speeches and Writings File contain information regarding his family life and early years.

The General Correspondence series is organized in two chronological sections: 1903-1933 and 1946-1952. Ickes's personal correspondence for the period in which he was secretary of the interior is in the Secretary of the Interior File , much of it under the heading "Friends." Ickes assisted in the 1905 mayoral campaign of John Maynard Harlan. Material on Progressivism and Theodore Roosevelt's relationship to the movement is found in files on Hiram Johnson, Donald Richberg, and Raymond Robins. Other political subjects discussed in the correspondence include the 1920 presidential campaign of James M. Cox. Charles Evans Hughes and the presidential campaign of 1916 are noted in files on Will H. Hays and James R. Garfield. The appointment of Progressives to political office in Chicago and in Illinois and the attempt by Hiram Johnson to take the 1924 Republican presidential nomination from Calvin Coolidge are discussed as well.

Ickes wrote regularly for the Progressive State Central Committee of Illinois, advocating such measures as product safety and the banning of literacy tests for immigrants as a requisite for voting. He was also involved during the 1920s in the People's Traction League, an association organized to combat the attempt by Samuel Insull to control rail service in Chicago during the period 1925-1930, and the People's Protective League, 1922-1923, through which Ickes and other Progressives blocked the passage of a revised Illinois constitution which they believed was not compatible with the needs of the people. These activities are documented in the first section of the General Correspondence file, as are such diverse interests as Ickes's stock market investments and his hobbies of growing dahlias and collecting stamps.

The second part of the General Correspondence series, 1946-1952, includes material on conservation issues, Ickes's interest in bringing the offshore oil issue before the Supreme Court for final settlement, planning for the hydrogen bomb, and corruption in government. An occasional file relates to his interests in legal matters. File names in both parts of the General Correpondence series refer to names of correspondents and to subjects of interest.

While Ickes was secretary of the interior, his personal correspondence and other material was filed separately from the Interior Department's official records and constitutes the largest single segment of the Ickes collection. Ickes was interested in Native American concerns and the treatment of the Japanese Americans during World War II. Other subjects include the governance of American territories such as Puerto Rico, oil and its effect upon society and business and as a dwindling natural resource, the early development of a Middle East pipeline and the formation of the Arabian-American Oil Company, the offshore oil dispute, presidential politics and Ickes's role in presidential campaigns, Franklin D. Roosevelt's cabinet and Ickes's disagreements with fellow cabinet officers Henry Morgenthau (1891-1967) and Henry Agard Wallace, and public works. Card indexes to the correspondence and speeches in this file are available in the Manuscript Division Reading Room.

The Secretary of the Interior File also includes drafts and final copies of articles, books, pamphlets, and speeches with related correspondence for the 1933-1946 period. The file indicates that although not all of Ickes's writings were from his own hand, he frequently reviewed and edited works written for him.

The Speeches and Writings File contains material from the period before and after Ickes's tenure as secretary of the interior, including reading copies, a printed set of speeches he delivered as secretary, and his memoirs, which he began to write shortly after entering Roosevelt's cabinet. The memoirs concern his education, family relationships, legal career, political interests, World War I experiences, and life in Chicago after the war. Comments on Ickes's political activities as a campaign manager include sketches of local Chicago political figures such as Fred Busse, John Maynard Harlan, and Charles Merriam. Another version of his memoirs was written for serialization in the Saturday Evening Post and possible later publication.

The Subject File supplements the General Correspondence . The Legal File includes material dated before 1933, a period not well documented in most other parts of the collection. Ickes represented clients in divorce suits, property settlements, and estate planning. He also represented trade associations and corporate interests and was occasionally involved in criminal cases. After he left public service, he represented a few clients in an advisory capacity.

Scrapbooks and miscellaneous material complete the collection. The Miscellany series includes printed matter, invitations, reports, memorabilia, financial journals, and a scheduling file of engagements and activities for the last six years of Ickes's life. The scrapbooks contain newspaper clippings compiled by Department of the Interior staff reflecting Ickes's achievements as secretary as well as compilations of personal memorabilia.

The Addition contains material obtained by the Library from other sources and added to the Ickes Papers. The bulk of this material consists of correspondence between Karl D. Vittum and Ickes, 1914-1917, regarding the Progressive Party of Illinois.

Ickes's diary and memoirs are also available on microfilm. The typewritten copy of his diary, 1933-1951, was subsequently withdrawn to prepare a published version and returned with approximately three hundred pages missing. The missing pages are thus included only in the microfilm copy. A list of the missing typescript pages appears in an appendix to this register. A third copy of the diary, consisting of a typescript for the years 1943-1951 with emendations by an editor, does not appear on the microfilm.

The index was filmed from photocopies which are available in the Manuscript Division Reading Room. Also available are index cards for the diary for 1946, an alphabetical card index to outgoing correspondence in the Secretary of the Interior File , and a card index, arranged by subject and location, to the speeches Ickes delivered as secretary of the interior.