Correspondence, speeches, and articles relating to the selection of a route for an isthmian canal and to Haupt's efforts to secure the Nicaraguan route. Includes records of the Nicaraguan Canal Commission and the Isthmian Canal Commission such as work papers, reports, minutes, memoranda, drawings and charts, news clippings, and copies of congressional hearings, speeches, and proposed bills. Correspondents include Newton Diehl Baker, William Jennings Bryan, Andrew Carnegie, John Hay, John Tyler Morgan, and Theodore C. Search. Includes letterbook (1861-1863) of Haupt's father, Herman Haupt, concerning his duties as chief of construction and operation of the U.S. Bureau of Military Railroads.