Correspondence, astronomical observations, geographical and meteorological data, expedition diaries, reports, research material, notes, maps, and other papers relating to Nicollet's explorations of the upper Mississippi and Missouri rivers. Documents his exploration of Minnesota, Missouri, South Dakota, and Wisconsin. Includes Francis A. Chardon's journals from Fort Clark, N.D.; Regis Loisel's account of the upper Missouri River; and excerpts from the diaries of Meriwether Lewis, William Clark, and Zebulon Montgomery Pike. Correspondents include Jacob Whitman Bailey, Edmund M. Blunt, Simon William Gabriel Bruté de Rémur, Jean-Louis-Anne-Madeleine Lefebvre de Cheverus, Pierce Connelly, Louis Régis Deluol, John England, David W. Gobel, J.D. Graham, F.R. Hassler, Ethan Allen Hitchcock, Charles T. Jackson, Elias Loomis, Alfred Mordecai, Rush Nutt, Joseph Plympton, Michael Portier, Joseph Rosati, H.H. Sherwood, Gerard Troost, and Sears Cook Walker.