Lewis and Clarks Expedition By Danneubauer May 21, 1804 Expedition Starts Feb 11, 1805 Sacagawea gives birth Jul 18, 1805 Reach three forks of the Missouri River They name these rivers the Gallath, Madison, and the Jefferson. Aug 17, 1805 Lewis finds a village Lewis finds a village of shoshones and trades for a horse Oct 16, 1805 expedition reachs the Columbia River