Pierre Gaultier de Varennes, sieur de La Vérendrye (17 November 1685 – 5 December 1749) was a French Canadian military officer, fur trader, and explorer. In the 1730s, he and his four sons explored the area west of Lake Superior and established trading posts there. They were part of a process that added Western Canada to the original New France territory that was centred along the Saint Lawrence basin. He was the first known European to reach present-day North Dakota and the upper Missouri River in the United States. In the 1740s, two of his sons crossed the prairie as far as present-day Wyoming, United States and were the first Europeans to see the Rocky Mountains north of New Mexico. Source: Wikipedia (en)