These are primarily papers relating to the work of the United States Army Corps of Topographical Engineers, with special reference to surveys of harbors of the eastern United States. Some papers and letters relate to natural history and are addressed to John Lawrence LeConte. Correspondents include Rutherford B. Hayes, Joseph Henry, Daniel Parker, and E.G. Squier.

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.