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.
St. Louis was founded in 1764 by French fur traders Pierre Laclède and Auguste Chouteau, and named after Louis IX of France. In 1764, following France's defeat in the Seven Years' War, the area was ceded to Spain and retroceded back to France in 1800. In 1803, the United States acquired the territory as part of the Louisiana Purchase. During the 19th century, St. Louis developed as a major port on the Mississippi River. In the 1870 Census, St. Louis was ranked as the 4th-largest city in the United States. It separated from St. Louis County in 1877, becoming an independent city