Pierre Daussy (October 8, 1792 - September 5, 1860) was a French astronomer and hydrographic engineer with the Bureau des Longitudes and later the Dépôt des Cartes et Plans de la Marine, which he led as Director in the years prior to his death. Daussy was born in Paris, the son of hydrographer Magloire Thomas Daussy (1758 - 1826). He followed in his father's footsteps, studying at the École des Ingénieurs Hydrographes before undertaking hydrographic work in the North Sea under the command of Charles-François Beautemps-Beaupré. He graduated to the rank of engineer in 1819 and chief engineer in 1829. In 1833, he began work with the Bureau des Longitudes correcting the French Table des Positions Géographiques des Principaux Lieux du Globe to conform with the most recent measurements made possible by new hydrographic instruments and methodologies. He was elected Director of the Dépôt des Cartes et Plans de la Marine in 1855. He also served as the President of the Société de Géographie de Paris in his later years and published several works on hydrography and navigation, particularly relating to the coasts of the Ottoman Empire and Persia.