An early settler and prominent citizen in the Moravian heartland near Bethlehem, Pennsylvania, Timothy Horsfield was named justice of the peace when Northampton County was formed out of Bucks in 1752, and was one of those given responsibility for the defence of the local white and Christian Indian populations during the French and Indian War. The Horsfield Papers offer a window onto the tumultuous history of northeastern Pennsylvania during the 1750s and 1760s. Comprised largely of correspondence and related documents between Horsfield, William Parsons, and provincial and military authorities, the collection includes important information on the Native tribes' actions (previously described as "Indian assaults") in the region in 1756 and 1757 and the military and diplomatic response of settlers.

The correspondence is principally to Zaccheus Collins (1810-1840), with bills, receipts, and notes on Rafinesque vs. Parker; letters from Collins, L.A. Tarascon, Lewis C. Beck, John Torrey, and Charles W. Short (1817-1835); and miscellaneous correspondence and documents relating to Rafinesque vs. Parker, with an account of the Felician Society of Feliciana County, Illinois (1820). The writings are chiefly on botanical topics, and include notes and essays on Indians, Blacks, grapes and wine-making, banking, and speculation. Rafinesque's growing interest in Indian antiquities, linguistics, and history is apparent in letters after 1820. There is an account of Rafinesque's scientific travels in North America and southern Europe (1800-1832), and a bibliography. The botanical notes include descriptions of specimens collected by Lewis and Clark, Patrick Gass, and Henry Muhlenberg.