Louis Marie Pantaléon Costa, Marquis de Beauregard (19 June 1806 – 19 September 1864) was a French statesman, archaeologist, historian and ornithologist.

[3] He was a member of the Académie des sciences, belles-lettres et arts de Savoie (1828) and was made a Commander of the Legion of Honour and a Knight of the Order of Saints Maurice and Lazarus.

[5][6] Beauregard refused a seat in the Senate proposed by Emperor Napoleon III in 1860, however, he became general councilor of the canton of Chambéry-Nord (in the Arrondissement of Chambéry) the same year and was elected president of the new General Council of Savoie, holding these offices until his death in 1864.

In his role as president of the Council, and together with Baron Frédéric d'Alexandry d'Orengiani (the mayor of Chambéry and the first Senator of Savoie, he welcomed Napoleon III and Empress Eugénie on 27 August 1860 during the imperial trip to Savoy.

[15] Through his second son Josselin, he was grandfather of Ferdinand-François-Marie-Pantaléon-Victurnien Costa, Marquis de Beauregard (1865–1953), who married Marie-Madeleine-Emilie-Victorine-Augustine Crombez in 1886.