Louis-Joseph de La Vérendrye

Louis-Joseph Gaultier de La Vérendrye was the youngest and most accomplished cartographer son of the explorer Pierre de La Vérendrye. Accompanying his father westward from youth, he mastered hydrographic surveying and Indigenous dialects, serving as commandant of Fort Kaministiquia on Lake Superior.

In April 1742, Louis-Joseph and his brother François set out from Fort La Reine on an extraordinary expedition across the northern Great Plains. Guided by Mandan warriors, they pushed southwest across the Dakotas, sighting the Bighorn Mountains on January 1, 1743. In Pierre, South Dakota, they buried a lead tablet claiming the territory for King Louis XV (rediscovered by schoolchildren in 1913). He died in the tragic 1761 shipwreck of the Auguste.