The collection consists of works, correspondence, documents, notes, photographs, and printed matter of Boyd. The bulk of the collection consists of organizational or topic-oriented correspondence relating primarily to Boyd's positions as a member of the board of directors (1952-1962) of the Thomas Jefferson Memorial Foundation; president and member (1964-1969) of the American Historical Association, which formed the Joint Committee for the Defense of the Rights of Historians Under the First Amendment with the Organization of American Historians in response to the lawsuit of Helen C. Frick against Sylvester K. Stevens and his book Pennsylvania: Birthplace of a Nation ; and president (1973-1976) of the American Philosophical Society which sponsored the bicentennial celebrations in Philadelphia and the acquisition of the Battle Abbey and Battle of Hastings sites for return to the British nation.

Included are a typescript of Fundamental Laws and Constitutions of New Jersey, 1664-1964, and miscellaneous manuscripts, press releases, and reviews related to the publication of The Papers of Thomas Jefferson (1950-1980), both edited by Boyd, as well as articles, lectures, addresses, and book reviews primarily dealing with Thomas Jefferson. There are also papers, mainly correspondence, from other affiliations: as editor (1928-1930) of the Susquehanna Company Papers for the Wyoming Historical and Geological Society; director (1932-1934) of the New York State Historical Association; librarian for the Historical Society of Pennsylvania; advisor to the Foundation Library Center, the John Simon Guggenheim Memorial Foundation, the Harry S. Truman Library Institute, and the Hall of Fame; trustee of the Institute for Advanced Study; member of the National Portrait Gallery Commission; and member of various Pulitzer Prize juries.

General correspondence includes letters from fellow historians, librarians, editors, educators, and friends, such as L. H. Butterfield, editor of the Adams Papers, W. H. Ferry of the Center for the Study of Democratic Institutions, James R. Wiggins, Oron J. Hale, Archibald MacLeish, Agnes Meyer, and Walter Muir Whitehall. In addition, there is correspondence with three presidents, Herbert Hoover, Franklin D. Roosevelt, and Harry S. Truman, as well as with Norman Thomas, Adlai E. Stevenson, Louis B. Wright, Philip M. Hamer, Whitfield J. Bell, and Felix Frankfurter.