Pierre Gaultier de Varennes, Sieur de La Vérendrye began his exploration of the Americas late in his life. Born in Quebec in 1685, he set up trading posts in the 1730s in the area of what is now the Canadian-American border. He had four sons who went with him on these expeditions.

Before that, though, Vérendrye fought in Queen Anne's War (1704é1705), in North America, and in Europe, in the War of Spanish Succession; during the latter, he was badly wounded at the 1709 Battle of Malplaquet.

Father and sons (Francois, Jean-Baptiste, Louis-Joseph, and Pierre) undertook a series of explorations westward during the 1730s and 1740s. They built a series of forts along the way to what is now North Dakota in 1738, resulting in a flourishing fur trade. Pierre made it to Lake Winnipeg and is thought to have been the first European to visit the Mandan Native Americans who lived in the area, and he established friendly relations with them and between other tribes, including the Cree and the Monsoni. They did encounter some hostile Native Americans. Pierre's son Jean Baptiste died in a struggle against Sioux in 1736.

Sons Francois and Louis-Joseph set out for the Missouri River in 1742. They made it to what is now South Dakota more than 60 years before Lewis and Clark did. The following year, the brothers set out to find the fabled Northwest Passage. They didn't find it. However, in 1743, after visiting Arikara Native Americans, they put down a lead plate declaring French sovereignty for as far as the eye can see. (Children found this plate, near Pierre, S.D., in 1913.) Also in that year, the sons Vérendrye are thought to have been the first Europeans to see the Rocky Mountains. They also saw two great rivers, the Missouri and the Saskatchewan; it was the latter that Pierre had thought would lead to the Pacific Ocean. They returned to Montreal and reported what they found.

Pierre resigned in 1743 to live the life of a gentleman. That retirement didn't last. He died in 1749, while planning another expedition west. Louis-Joseph, the older son, fought in the French and Indian War and died when a ship he was on sank, in 1758. Pierre, the next oldest son, died in Montreal in 1755. Francois, the youngest son, fought in the French and Indian War and died in 1794.