Slavery in the colonial United States in the Caribbean: Guadeloupe and especially Saint-Domingue.) After the port of New Orleans was founded in 1718 with access to the Gulf Coast, French colonists imported more African slaves to the Illinois Country for use as agricultural or mining laborers. By the mid-eighteenth century, slaves accounted for as many as a third of the limited population in that rural area. Slavery was much more extensive in colonial Louisiana, where the French developed sugar cane plantations along the Mississippi river. Slavery was maintained during the French (1699 – 1763, and 1800 – 1803) and Spanish (1763 – 1800) periods of government.
New France was returned to the king. Louis XV saw no value in Louisiana, and in order to bring about an end to the Seven Years' War, he transferred Louisiana to his cousin Charles III of Spain in 1763. Louisiana remained under the control of Spain until it was demanded to be turned over to France by Napoleon. Although Louisiana was property of France by the Third Treaty of San Ildefonso in 1800, Louisiana continued to be administered by Spain until the Louisiana Purchase in 1803. Following the Louisiana purchase, the population of the subsequently divided territory that contained most of present-day