Scope and Content Note
The papers of Harman Blennerhassett (1765-1831) span the years 1755-1866 and consist of journals, business and family correspondence, legal and financial papers, and miscellaneous material. The trial of Aaron Burr for treason, the indictment of Blennerhassett for conspiracy with him, and the subsequent misfortunes experienced by the Blennerhassett family are revealed in Blennerhassett's three-volume journal, 20 July-20 Nov. 1807, his correspondence with his wife, Margaret Agnew Blennerhassett (died 1842), and a manuscript volume attributed to his son, Harman Blennerhassett (1801-1854).
Other correspondents include Henry William Paget, the Marquis of Anglesey, Dominic Blennerhassett (born 1799), Joseph Lewis Blennerhassett, Henry Clay, Nathaniel Cox, Robert Emmet, John Langley, Joseph S. Lewis, Mordecai Lewis, Thomas Mullins, Vincent Nolte, Sir Robert Peel, Joseph Tyndall, Richard S. Wheatly, and Dudley Woodbridge.