Kimball served as a juror in the competition for a design of a memorial on the St. Louis river front to mark the western expansion of the United States. The subseries includes offical publications of the competition; jury reports; correspondence, primarily with George Howe, advisory architect, and William Wurster, chairman of the jury; photographs of Eero Saarinen's winning design for the St. Louis Arch; lists of competitors; and newspaper clippings.