The first volume is minutes of the commissioners for determining the line between Pennsylvania and Maryland, which was copied by George M. Justine in 1842 from an "authenticated" copy owned by Ferdinand R. Hassler. The second volume contains receipts (62 items) for money spent by the Penn family for the survey.

Between 1764 and 1781, the Scots surveyor George Gauld was assigned by the British Admirality to chart the waters of the Gulf Coast off British West Florida, an area that extended from New Orleans to the modern-day Florida. In 1773, Gauld submitted some of his findings to the APS, probably in hopes of having them published in the Transactions, and although these were not published, they became one of the first mansucripts entered into the Society's collections. Contains occasional brief references to Native peoples of the areas described. The Gauld manuscript also includes an extract of a letter from John Lorimer to Gauld, 1772, and a sketch of the Middle and Yellow Rivers of West Florida by Thomas Hutchins. When it was received at the APS, it was endorsed: "This long uninteresting Paper can hardly obtain a Place in the Transactions of a Philosophical Society. It should however be preserved in the Files for the Use of Historians or map makers."

Correspondence from Charles Mason and Jeremiah Dixon to Thomas Birch, and Nevil Maskelyne to Charles Mason, relating to the survey, and the transits of Venus (1761,1769).

These letters relate principally to provincial business and comment on the Indians of Pennsylvania, the French and Indian War, a survey of the Maryland-Pennsylvania boundary, and the Stamp Act. Correspondents include James Burd, Jeremiah Dixon, Joseph Galloway, Humphry Marshall, Charles Mason, Edward Shippen of Lancaster, and Edward Shippen, Jr.

Three volumes contain letters, laws, charters, reports, proclamations, petitions, and other official and semi-official documents relating principally to early Pennsylvania and New Jersey, signed by or addressed to William Penn, among others. A fourth volume is Penn's cash book, 1699-1703, which records expeditures, payments of quit rents, etc. Tipped in is "Catalogue of Goods left at Pensbury," and of goods left at Philadelphia, 1701.

Letters (including some transcripts and photostats) from and to Vaughan from many American and British correspondents, including: Also personal correspondence and business papers of Benjamin, Charles, Petty, Samuel Sr., Samuel Jr., William, William Oliver, and Sarah Vaughan (2 boxes); lectures, mostly in shorthand (3 vols.); a large number of notes and memoranda on a wide variety of topics, such as agriculture, architecture, astronomy, diplomacy, diseases, dueling, electricity, hieroglyphs, internal improvements, medicine, meteorology, land, manufactures, politics, punctuation, religion, silk-manufacturing, stock-breeding, taxation, Unitarianism, Benjamin Franklin, John Locke, Napoleon I, Joseph Priestley, Bowdoin College, town of Hallowell, Maine; notes on the peace negotiations, 1782-1783; miscellaneous legal papers; genealogy of the Abbott-Vaughan families. For a personal account of the collection, see Mrs. Mary Vaughan Marvin, "The Benjamin Vaughan Papers," APS Proceedings 95 (1951): 246-249.

These letters and papers include ten small volumes of letterbooks (1752-1781), and ca. 100 pieces of correspondence with Joseph Shippen (1750-1778). Topics discussed are business in Philadelphia and Lancaster, provincial politics, army supply in the French and Indian War, land purchases and speculation, housebuilding, and family affairs.