Expedition of Lewis and Clark By graceradulovic May 14, 1804 The Corps of Discovery departs from Camp Dubois Period: May 14, 1804 to Sep 23, 1806 The Expedition Jun 1, 1804 The expedition reaches the Osage River Jul 21, 1804 They reach the Platte River, entering Sioux territory Aug 20, 1804 Sergeant Charles Floyd dies, only memeber lost during expedition Sep 7, 1804 Crew finds, kills, and logs the newly found prairie dog Nov 4, 1804 Captains meet Sacagawea Apr 25, 1805 Arrive at Yellowstone river, discovery of the Big Horn Sheep May 5, 1805 Lewis and hunters find and kill first grizzly bear Aug 13, 1805 Lewis meets Cameahwait, a leader of Shoshone Aug 15, 1805 Lewis and crew set up Camp Fortunate Sep 1, 1805 Begin crossing the Bitterroot Mountains Nov 20, 1805 Encounter the Pacific Ocean at the mouth of the Columbia River Mar 22, 1806 Corps of Discovery leave Ft. Clatsop to voyage back east Jun 30, 1806 Camped at Traveler's Rest in Montana Jul 3, 1806 Corps of Discovery split into two groups Jul 7, 1806 Lewis' group crosses the Continental Divide Sep 23, 1806 The Corps arrives in St. Louis, ending their journey after 2 years