On a hill above the Missouri River at Fort Pierre, members of the La Vérendrye expedition buried a lead plate in March 1743 to claim the surrounding region for France during a westward journey aimed in part at reaching the Pacific. Usually associated with Louis-Joseph and François de La Vérendrye, this leg of the expedition formed part of broader French exploration and trade expansion across the northern plains. The site gained lasting importance when the plate was rediscovered in 1913, providing the first written evidence of a European visit to what is now South Dakota and helping scholars better trace the expedition’s movements.