A city and port in southeastern Louisiana, on the Mississippi River; population 311,853 (est. 2008). Founded by the French in 1718, it was named after the Duc d'Orléans, regent of France. It is known for its annual Mardi Gras celebrations and for its association with the development of blues and jazz. In 2005, Hurricanes Katrina and Rita caused extensive devastation and loss of life when the levees failed, leaving floodwaters to engulf the city.