The collection consists of selected manuscripts, correspondence, and documents of Witherspoon, as well as material about him. Among the manuscripts are a Latin address (1783) to the trustees at Princeton, a Latin oration (1794), and fragments of a sermon (undated). There are receipts (1779) for four Scottish prisoners-of-war, for whom Witherspoon made himself accountable; over twenty letters (1767-1768) by Witherspoon to Benjamin Rush, who was then a medical student in Edinburgh, Scotland; and letters to John Bayard, Henry Lee, James Madison, Jonathan Sergeant, George Washington, and others. One letter (1787) to St. George Tucker discusses Witherspoon's theory of education and the establishment of a grammar school. A signed circular letter (1784) to the Presbytery of New Brunswick seeks funding support in order to deal with consequences of the American Revolution on the College of New Jersey (now Princeton University) campus. Also included are receipts and bills from the Treasurer's Office of the College of New Jersey, two deeds, and notes taken by Abel Johnson (Princeton Class of 1784) of Witherspoon's history lectures. There are also documents regarding a case filed by Witherspoon in a court in the City of New York, dated 4 June 1793, against Lewis Morris for money owed to Witherspoon.

Additional accessions include material of John Witherspoon as well as material of members of his family. Included are letters by Witherspoon--one to his son David, another addressed "To the Public" (1774), and a letter to Aaron Burr--and material related to the legal suit of Witherspoon vs. Lewis Morris. There are deeds for land signed by Witherspoon's second wife, Ann, to satisfy debts against his estate. Also among the additions are some correspondence of his daughter Marianne Witherspoon Woods and her children, John Witherspoon Woods, Francis W. Woods, James S. Woods, and Margaret J. Woods, a receipt of Witherspoon's son David, and correspondence of other members of his family.