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 first volume includes extracts from the journals of Conrad Weiser and Christian Frederick Post (1757), Charles Thomson's "An Enquiry into the causes of the alienation of the Delaware and Shawanese Indians from the British interest" (1759), and a printed version of Judge Bradford's "Statement of facts and observations respecting the penal laws" (1792). The second volume contains selected letters and documents in the Pennsylvania state records on Indian relations, including transcriptions of several treaties between the Province of Pennsylvania and the Delawares and other Indians (1755-1758); the French and Indian War; and Braddock's campaign. Some manuscripts are written by Deborah Norris Logan and Charles Thomson.

A product of the distinctive culture of reform in antebellum Philadelphia, William Parker Foulke was the scion of the old elite who put a conservative stamp on social change. Trained as an attorney, Foulke spent much of his adult life engaging his deep amateur interest in natural history and mental philosophy and devoting himself to a variety of civic and philanthropic causes, including the colonization of formerly enslaved persons, penal reform, and cultural institutions in his native Philadelphia. The Foulke Papers are the product of the diverse social and intellectual interests of the Philadelphia attorney and philanthropist William Parker Foulke. Consisting primarily of correspondence, notes, and essays, the collection touches on Foulke's many interests. The collection includes numerous lectures delivered by Foulke along with material on the Lancaster County Prison, New York Prison Association, and the Philadelphia Society For Alleviating the Miseries of Public Prisons; notebooks concerning prisons and prisoners, including a 1846-1852 diary, and a listing of prisoners, their race, age, crime, sentence, and observations; a diary concerning the American Colonization Society (1852); a copy of an arctic diary (1853-1854) by John Wall Wilson, in the hand of Isaac Israel Hayes, which recounts much of the journey aboard the brig Advance, commanded by Elisha Kent Kane. There is also a list of buildings (1820-1841) designed by John Haviland, and material on the American Academy of Music, Philadelphia.