Soon after the sieur de Bienville had the city platted in 1718 it became an important port, and in 1722 it became the capital of the French colony. The transfer of Louisiana to Spain by the secret Treaty of Fontainebleau (1762) was confirmed by the Treaty of Paris (1763). New Orleans—deeply involved in the struggle for control of the Mississippi—was returned to French hands only briefly before passing to the United States with the Louisiana Purchase (1803). From 1809 to 1810 some 10,000 refugees from the slave revolt in St. Dominigue (later Haiti) who had previously fled to Cuba emigrated to New Orleans, doubling the population. The tone of the city's life was dominated by Creole culture until late in the 19th cent., and the French influence is still seen today.
After Andrew Jackson's victory over the British at New Orleans (Jan. 8, 1815) had written a postscript to the War of 1812, the westward movement in the United States carried the queen city of the Mississippi to almost fabulous heights as a port and market for cotton and slaves. New Orleans then was stamped with its lasting reputation for glamour, extravagant living, elegance, and wickedness. Then as now African Americans were a large element in the population, and they contributed to the cosmopolitan flavor of the city. The quadroon balls—sumptuous affairs attended by rich white men and their quadroon mistresses—disappeared with the Civil War, but African folkways and stories of voodoo magic persisted into the 20th cent.
The golden era ended when in the Civil War the city fell (1862) to Admiral David G. Farragut and suffered under the occupation by Union troops led by General Benjamin F. Butler. New Orleans recovered from Reconstruction and passed through the end of the river-steamboat era to emerge as a modern city. Its past, however, is perhaps a greater factor than the warm damp climate in attracting visitors and artists and writers. The unusual life and history of the city have produced its own literature, including the works of George W. Cable, Lafcadio Hearn, Grace Elizabeth King, Charles Gayarré, and Alcée Fortier. Jazz had its origin in the late 19th cent. among the black musicians of New Orleans.
The first attempts to integrate New Orleans public schools aroused controversy in 1960. Since then blacks have come to comprise the large majority of students and teachers in the school system, as many whites have moved to the suburbs. In 1969 Hurricane Camille swept through the region, resulting in many deaths and much property damage. Since the 1960s the population of the metropolitan area has risen at a rate slightly higher than that at which the population of the city has declined, reflecting the trend toward suburbanization that has left the inner city troubled by poverty.
Attempts have been made at urban revitalization; in the 1970s many new buildings were erected as the city benefited from high oil prices. In the 1980s, however, the economy suffered as oil prices fell and the state's energy industry floundered. In 1983 New Orleans hosted a world's fair, but the attention it attracted and its economic contribution fell far below expectations. Gambling was legalized in 1992, but the introduction of riverboat and casino gambling proved unsuccessful and failed to provide the anticipated impetus to the city's economy.
On Aug. 29, 2005, Hurricane Katrina brought extensive flooding to the city when several levees failed. Much of the city was evacuated before the storm but thousands remained, many of whom were stranded by the water for days; hundreds died. In the aftermath, many residents could not return because their homes had been destroyed and established new lives elsewhere, greatly reducing the city's population. A 2006 survey showed that the population was approximately 40% of what it was estimated to have been before the storm. In the aftermath of the flooding, an improved system of levees and flood walls, flood gates, and pumps was constructed at a cost of $14.5 billion.