The history of New Orleans is closely tied to the Mississippi River and its use for shipping into the interior of the United States. The mouth of the Mississippi was extremely shallow and unsuitable for boats when the French settlers arrived in the area. The route chosen to access navigable portions of the Mississippi River included a portage at the site of Baton Rouge, but in 1699, the brothers Bienville and Iberville were shown an easier route by the friendly Choctaw Indians. The brothers founded the city of New Orleans in 1718 at the point where the two mile portage from Bayou St. John crossed the natural levee to the Mississippi River.

Louisiana remained a French colony until it was ceded to the Spanish in 1763, but Spain did not attempt to take possession of it until 1766. The Govenor sent by Spain was forced to flee by a rebellion in 1768, and Spain was required to send troops to retake New Orleans a year later. Following several fires early in the Spanish rule that destroyed most of the buildings in the city, the citizens soon learned to build with native cypress and brick. The Spanish established new building codes requiring tile roofs and brick walls. A walk through the French Quarter today, shows that the architecture is really more Spanish than French.

The Spanish Crown returned New Orleans and the Louisiana territory to France, under pressure from Napoleon, in a secret treaty signed in 1800. The new French Governor was not assigned until 1803 and arrived in New Orleans three weeks prior to the announcement of the Louisiana Purchase, selling the city and a vast area of the North American continent to the United States. Unlike the transfer to Spanish rule, the citizens of New Orleans were happy with the change, since most of the trade in the area was with the U.S.

During the War of 1812, the British sent a force to try to conquer New Orleans, but they were defeated by forces led by Andrew Jackson some miles down river from the city at Chalmette, Louisiana, in a battle commonly known as the Battle of New Orleans. Early in the Civil War, New Orleans was captured by the Union without a battle in the city itself, and was spared the destruction suffered by many other cities of the American South. It retains a historical flavor with many 19th century structures far beyond the confines of the French Quarter.