Maria Eleonora I Boncompagni (1686–1745) was the Princess of Piombino, Marchioness of Populonia, Princess of Venosa and Countess of Conza, Lady di Scarlino, Populonia, Vignale, Abbadia del Fango, Suvereto, Buriano, Cerboli e Palmaiolan, and Lady princess of the Tuscan Archipelago including the islands of Elba, Montecristo, Pianosa, Gorgona, Capraia, and Isola del Giglio, from 1733 until her death.