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).

A Sachem and Civil War adjutant to Ulysses Grant, Ely Samuel Parker was an important figure in the Seneca Indian nation during the first half of the nineteenth century. Trained as an engineer, Parker was deeply involved in the Senecas' land disputes with the Ogden Land Company and he played an important role in interpreting Seneca culture for a white audience, most notably as a consultant for Lewis Henry Morgan. Collected by Arthur C. Parker, the Ely Samuel Parker Papers include correspondence, manuscripts, and printed materials relating primarily to Seneca affairs, history, language, and culture, as well as politics, education, engineering, and the Civil War. Among Parker's correspondents were Henry Clay, Millard Fillmore, Henry M. Flagler, Lewis Henry Morgan, Henry Rowe Schoolcraft, Daniel Webster, and Asher Wright. Several letters relate to Parker's service as engineer of public buildings in Galena, Illinois, and to his Masonic activities. Among the noteworthy items in the collection are several essays on Seneca history and culture, a fragment of Parker's diary, 1847, and a significant quantity of material on the Seneca language assembled by Asher Wright.

The Thomas Jefferson papers contain a large number of correspondence both to and from Jefferson, as well as various other material related to American Revolutionary War and Early Republic. Includes correspondence with Patrick Henry, Charles Willson Peale, Richard Henry Lee, Horatio Gates, David Rittenhouse, Robert Patterson