Pierre Gaultier de Varennes, sieur de La Vérendrye (November 17, 1685 – December 5, 1749) was a French Canadian military officer, fur trader and explorer. In the 1730s he and his four sons opened up the area west of Lake Superior and thus began the process that added Western Canada to the original New France in the Saint Lawrence basin. He was also the first known European to reach North Dakota and the upper Missouri River. In the 1740s two of his sons crossed the prairie as far as Wyoming and were the first Europeans to see the Rocky Mountains north of New Mexico.