This feature was added  in following with the general practice of many of the early Indiana biographical records. Most of these documents espouses that those listed within were "Representative Men" of their community and, to enhance this proclamation, some included biographies of the United States Presidents. Perhaps another reason the publishers included these was to simply enhance the size of the document! You will note that this document lists all the Presidents of the United States with photos and links, however, the biographies end with William McKinley which coincides with the scope of this site.