This collection contains mostly entomological material, with much information on the description and identification of particular insects, entomological collections, and the study of entomology in Europe and the United States. In addition, there are materials on medicine and hospitals during the American Civil War, on the Corps of Topographical Engineers, the United States Army, on natural history in the United States, and on the LeConte's family. Some letters are written to President Rutherford B. Hayes and concern the Commissionership of Agriculture, for which LeConte was considered, but not appointed. Letters of John Eatton LeConte and Joseph LeConte are included.

The collection includes letters between Hutchinson and his uncle Israel Pemberton, written while Hutchinson was a student of medicine in London. There are also 12 tickets of admission to medical lectures in Philadelphia and London, including one given by William Hunter, and 3 unused cards of admission to Hutchinson's own lectures. Miscellaneous items include Hutchinson's marriage certificate; genealogical data on the Hutchinson, Hare, and Pemberton families; and stock certificates, 1857-1872, of the McKean and Elk Land and Improvement Company. Materials dated post-1793 are to and from Hutchinson family members.