The Lewis and Clark Expedition By TylerGavin Mar 4, 1801 President Jefferson's first day in office Apr 30, 1803 The Louisiana Purchase May 14, 1803 The Expedition starts Aug 20, 1804 Sergeant Charles floyd dies Floyd was the only member to die on the expedition. Period: Oct 24, 1804 to Apr 7, 1805 The Corps Stay at the Mandan Villages for the Winter Nov 7, 1804 Toussaint Charbonneau and Sacagawea join the Expedition Feb 11, 1805 Sacagawea's baby, Jean Baptiste, is born May 26, 1805 The Corps of Discovery sights the Rocky Mountains Jul 27, 1805 The Corps reaches the Three Forks of Missouri Sep 23, 1806 The Corps of Discovery returns to St. Louis