President Thomas Jefferson asked Congress to finance an expedtion to explore the western part of North America. Congress quickly approved the request.
U.S. representatives signed a treaty with Grance to purchase the Lousiana Territory
Captain Meriwether Lewis, Jefferson's choice to lead the expedtion, asked William Clark to serve as co-leader
Lewis launched the expedition boat down the Ohio River from Pittsburgh, Pennsylvania
Lewia and Clark met in Clarksville, Indiana, where Clark had recuited men for the expedition
The expedition estabilished winter quarters at Camp Dubois, near St. Louis, Missouri
The expedition set out from Camp Dubois and headed up the Missouri River
Sergeant Charles Floyd became the expedition's only member to die on the journey.
The group began to build Fort Mandan in present-day North Dakota for its winter camp
Lewis and Clark the French-Canadian fur trader Toussaint Charbonneau and his Shoshone Indian wife Sacagawea to interpret Indian languages
The journey resumed up the Missouri River.
The group reached the Great Falls of the Missouri River and soon began an 18-mile (29-kilometer) overland trip around the waterfalls
The expedition entered the Lolo Trainl of the Bitterroot Range in the Rocky Mountains. The party spent 11 days crossing the mountains under severe weather
Members of the expedition reached the Pacific coast
The expedition began to build Fort Clatsop in presetn-day Oregon for its winter quarters
The homeward journey started
The expedition split into two groups to find a shortcut home and to explore more of the Louisiana Territory
Lewis's group killed two Blackfeet Indians who tried to stal guns and horses in what was the only bloodshed on the entire trip.
The two groups of explorers reunited on the Missouri River, near the mouth of the Yellowstone River