Papers of the American editor, railroad commissioner, executive secretary to New York State Governor Levi P. Morton. Incoming correspondence concerning railroads (Avery Andrews, Paul D. Cravath, Chauncey M. Depew, James Jerome Hill, Jeremiah Jenks, Theodore Roosevelt); politics (Thomas Collier Platt, L. Bradford Prince); the John Ericsson monument in New York City (Jonathan Scott Hartley); and the personal life of actress Louise D. (Mrs. Leslie) Carter.

Papers of the American lawyer, politician, U.S. Secretary of War under President McKinley, U.S. Secretary of State under Theodore Roosevelt, following the death of John Hay, and United States Senator from New York. Letters, 125 of which are outgoing, which include discussions concerning national and state Republican Party politics. Several letters are responses to speaking and/or dinner invitations as well as recommendations for various appointments. Correspondents include Cephas Brainerd, Henry Billings Brown, Charles Butler, Julius Chambers, Henry J. Cookinham, William E. Curtis, Charles B. Elliott, Robert Ely, John H. Finley, Henry W. Fishel, Jacob Gallinger, Paul Hickok, Frank Wayland Higgins, Willis Johnson, Adrian Joline, John Knox, Samuel Koenig, Chester Lord, Isabel Lord, William McAdoo, Richard McCurdy, Martin McMahon, Charles Miller, Benjamin B. Odell, William C. Osborn, Ellis Robb, Arthur Saunders, and others.

Papers of the Congressman from New York, United States minister to France, Vice-President of the United States, and Republican governor of New York State. Collection contains mostly incoming correspondence from clergymen, educators, financiers, journalists, and politicians. Some letters are addressed to Morton's executive secretary, Ashley W. Cole.