Louisiana became a royal colony of France in 1731 but the French were disappointed with the small income produced in the colony. In 1762, France secretly ceded to Spain the Isle of Orleans, which included New Orleans, and the area of Louisiana west of the Mississippi River. French colonists learned of the transfer in 1764 and became angry. In 1768, a band of Frenchmen drove out the Spanish governor. But Spain took firm control of its new possession in 1769.

Between the 1760's and 1790, about 4,000 French settlers from Canada arrived in Louisiana. British troops had driven them from their homes in Acadia, in eastern Canada. The Acadians settled chiefly along the Teche, Lafourche, and Vermilion bayous. Their descendants came to be known as Cajuns.

During the Revolutionary War in America (1775-1783), Spain allowed agents of the Continental Congress to use New Orleans as a base. These agents shipped supplies up the Mississippi and Ohio rivers to the struggling American Colonies.

Louisiana prospered under Spanish rule. The government was stable, and encouraged business and commerce. The Louisiana sugar industry began in 1795, when etienne de Bore developed a method of processing sugar on a large scale. Louisiana planters began growing sugar cane as a major crop. In 1800, France secretly persuaded Spain to return Louisiana to France. However, Spain kept the region until November 1803 when it was sold to the United States. See Louisiana Purchase.