Harman Blennerhassett (1765-1831) was an American adventurer, who, with Aaron Burr, was accused of treason. He was born in Hampshire, England, on October 8, 1765. Educated at Trinity College, Dublin, he was admitted to the bar in Ireland in 1790, then traveled widely in Europe. Ostracized by his family when he married his 18-year-old niece in 1796, Blennerhassett emigrated with his bride to America. Two years later he bought the island in the Ohio River near Parkersburg, Va. (now West Va.), that still bears his name. There he built a luxurious mansion, where he lived as a gentleman scholar until he met Aaron Burr in 1805.
Lonely and gullible, Blennerhassett quickly fell in with Burr's vague imperial scheme and pledged the remains of his fortune to its success. In 1806 the island was the starting point for Burr's expedition. President Jefferson's proclamation denouncing the conspirators reached the area after the leaders had set sail, but militiamen descended on the island, looting and vandalizing. Early in 1807, Blennerhassett was arrested and indicted for treason, but the charges were dropped when Burr was acquitted.
Friendless and in disgrace, his wealth dissipated and his island mansion destroyed, Blennerhassett failed first as a cotton planter in Mississippi and then as a lawyer in Montreal. In 1822 he returned to Europe, where he died on the island of Guernsey on February 2, 1831.