Pierre Laclede (pyĕr läklĕd´), c.1724–1778, French pioneer in the United States. His surname was Liguest, but he adopted the name Pierre Laclede. He went to New Orleans in 1755 and was a member of the fur-trading firm that received (1762) a monopoly of the fur trade of the Missouri region. Accompanied by his stepson René Auguste Chouteau, he led a party up the Mississippi River to found a trading post. Since the region east of the river was transferred to Great Britain in 1763, Laclede established (1764) his post on the west bank. It was the beginning of the city of St. Louis.