Henry Howard (1818–1884) was an Irish-born American architect. Over the course of four decades, he designed over 280 buildings in Louisiana, including several plantation houses during the antebellum era. After the Civil War, he designed many town houses in New Orleans.

James Gallier was a prominent nineteenth-century Irish-born American architect, most famed for his buildings in New Orleans. Gallier Hall, which he designed and once served as New Orleans City Hall, is named after him.