Papers of the Army officer; U.S. Senator (1845-1849); U.S. Secretary of the Treasury. During the Civil War, President Lincoln commissioned Dix a major-general, and ordered him to take charge of the Alexandria and Arlington Department, then reassigned him to the Department of Maryland. Dix later served as commander of the Department of the East. After the Civil War, Dix was named Minister to France (1866-1869), and following his return to the U.S., the life-long Democrat became the Republican Party nominee and the successful candidate for the Governorship of New York State (1873-1875). Includes more than 130 items of outgoing correspondence, more than half of which were written to Edwards Pierrepont between 1861 and 1877. Subjects include the Civil War, Reconstruction, New York State and national politics, and French politics and foreign relations preceding the outbreak of the Franco-Prussian War.

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.

Papers of the Lawyer, New York State governor, presidential candidate, U.S. Secretary of State. Outgoing correspondence, with the exception of two incoming letters from Horatio C. King and George B. McClellan. Most of the letters are responses to recommendations for various appointments and speaking invitations. Letters to John Barrett, Princess Bibesco, Joseph Buffington, Samuel P. Cadman, Samuel M. Cavert, Edward Fallows, Bert M. Fernald, Roy G. Fitzgerald, Julius Frank, Robert H. Fuller, Martin H. Glynn, Paul Hickok, Hamilton Holt, R. U. Johnson, Winfield Jones, William A. Nash, Clarence Owens, Robert Paine, Amasa J. Parker, George Pratt, Palmer Ricketts, E. Quincy Smith, Robert E. Speer, Frederic J. Stimson, Charles Vrooman, Albert H. Walker, Henry Wallace, George W. Wickersham, and Sidney Woodward.

Incoming and some outgoing correspondence of the New York State Congressman and Governor, mainly from his term in the House of Representatives.

Papers of the New York State Governor, 1901-1904. Both incoming and outgoing correspondence, three items of which concern the selection of Ray Brook as the proposed site of the State Hospital for consumptives. Correspondence with Horatio Collins King, Anson G. McCook, John G. McCullough, Nathan L. Miller, Henry Codman Potter, and others.