Correspondence, family papers, speeches, autobiographical and biographical writings, subject files, notes, scrapbooks, clippings, printed material, and other papers relating principally to Hughes's service as governor of New York (1907-1910), U.S. secretary of state (1921-1925), associate justice (1910-1916) and chief justice (1930-1941) of the U.S. Supreme Court, and member of various international bodies and commissions. Includes papers of Hughes's father David Charles Hughes (1832-1909) and biographical writings by Merlo John Pusey and Henry C. Beerits.

Topics include New York state politics, the presidential election of 1916, World War I reparations, the Washington Conference on Limitation of Armament (1921-1922), International American Conference in Havana (1928), Japanese immigration, smuggling of alcohol, relations with Latin America, dispute between Peru and Chile over the provinces of Tacna and Arica, the boundary dispute between Honduras and Guatemala, the International Court of Justice, and the Permanent Court of Arbitration.

Correspondents include Nicholas Murray Butler, Calvin Coolidge, Charles Gates Dawes, Felix Frankfurter, Warren G. Harding, George Brinton McClellan Harvey, Herbert Hoover, Alanson Bigelow Houghton, William E. Jillson, J. J. Jusserand, Frank B. Kellogg, Henry Cabot Lodge, John Van Antwerp MacMurray, John Bassett Moore, Franklin D. Roosevelt, Theodore Roosevelt (1887-1944), Elihu Root, C. Bascom Slemp, Harlan Fiske Stone, William H. Taft, Willis Van Devanter, and Woodrow Wilson.