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.

Trained as an anthropologist under Frank Speck at the University of Pennsylvania, the ethnohistorian George Snyderman (1908- ) spent his career studying Seneca Indian religion, history, and culture. Snyderman edited the previously unpublished diaries of Halliday Jackson and John Phillips, Quaker missionaries to the Senecas in the late 18th and early 19th century. The Snyderman Papers includes a small volume of correspondence, along with manuscripts of works by Snyderman and colleagues, and copies of primary source materials pertaining to Seneca history. Of particular interest is his correspondence with anthropologists William N. Fenton, Merle Deardorff, and Frank Speck and with his Seneca consultant Clara Redeye and her daughter, Helen Harris, and photographs of the Allegany Senecas taken by Fenton and Speck.