was a merchant ship out of Philadelphia, United States during 1800.
During Quasi-War with the French, the Louisa carried a letter of marque allowing her to act as a privateer. She was armed with twelve six-pound guns and manned by a crew of thirty (including officers).
In August 1800 the ship was attacked off Gibraltar by French privateers from Algeciras. During the battle, the captain, Thomas Hoggard (Thomas Haggard), was wounded and taken below to his cabin. The Louisa eventually fought off the attack and Hoggard was taken ashore at Gibraltar where he died.
The USS Haggard (DD-555) was named in honor of the actions of Louisa's captain and crew off Gibraltar.
- Louisa. Privateer out of Baltimore, War of 1812.
- Louisa. Privateer out of Buenos Aires, taken over by crew, October 1818, to be used for piracy.
- Louisa. Whaling schooner, 35 tons. Built at Hobart, 1834, foundered near Bruny Island, 22 October 1836. All hands lost.
- Abbot, Willis J. (illustrations, Ray Brown). American Merchant Ships and Sailors. New York: Dodd, Mead & Company (1902).
- Hall, John E. (editor). "Recollections of a Voyage to Italy in the year 1800." The Port Folio and New-York Monthly Magazine, II-3 (September 1822) 207-236. Philadelphia: Harrison Hall (1822).
- Maclay, Edgar Stantan. A History of the United States Navy, from 1775 to 1894. New York: D. Appleton and Company (1895).
- Pennsylvania Magazine of History and Biography, The Vol. XXIII. Philadelphia: Historical Society of Pennsylvania (1899).