Expedition Timeline
January 18, 1803
Expedition Event
Jefferson sends a secret letter to Congress asking for $2,500 to finance an expedition to explore the Missouri River. The funding is approved February 28.
February 24
World Event
Marbury v. Madison ruling by Supreme Court asserts Constitutional Right of Judicial Review.
February 28
Expedition Event
Congress approves Jefferson's request.
March 1
World Event
Ohio becomes the 17th U.S. State.
April-May
Expedition Event
Jefferson sends Lewis to Lancaster and Philadelphia, Pennsylvania, to be tutored by some of the nation's leading scientists (including Benjamin Rush, Benjamin Smith Barton, Robert Patterson, and Caspar Wistar). He also purchases supplies needed for the Expedition.
April 30
World Event
Robert Livingston and James Monroe conclude a treaty in Paris in which the United States purchases the 827,000-square-mile Louisiana territory from France for $15 million.
May 18
World Event
Great Britain declares war on France.
May 25
World Event
American essayist and philosopher Ralph Waldo Emerson is born.
June 19
Expedition Event
Lewis writes to William Clark, asking him to co-lead the expedition up the Missouri. Clark accepts, in a letter dated July 18.
June 20
Expedition Event
Jefferson addresses his instructions to Lewis.
July 4
World Event
The United States' purchase of the 820,000-square mile Louisiana territory from France for $15 million is announced.
July 5
Expedition Event
Lewis leaves Washington.
July 6
Expedition Event
Lewis stops in Harpers Ferry (in present-day West Virginia) and purchases supplies and equipment.
July 23
World Event
Robert Emmett leads an abortive revolt against the British in Ireland.
July-August
Expedition Event
Lewis spends over a month in Pittsburgh overseeing construction of a 55-foot keelboat. He and 11 men head down the Ohio River on August 31.
September 23
World Event
British Officer Lt. Wellesley defeats Marathas in India.
October 14
Expedition Event
Lewis arrives at Clarksville, Indiana Territory, across the Ohio River from present-day Louisville, Kentucky, and meets up with William Clark. Clark's slave York and nine men from Kentucky are added to the party.
December 8-9
Expedition Event
Lewis and Clark arrive in St. Louis and decide to set up camp for the winter on the east bank of the Mississippi River. At Camp Dubois (also known as Camp Wood), they recruit more soldiers, train them, and stock up on supplies.
December 20
World Event
Louisiana is officially transferred to the United States from France. The United States takes formal possession December 30 at a ceremony in New Orleans.
January 1, 1804
World Event
Haiti gains its independence from France, becoming the world's first black republic.
February 15
World Event
New Jersey abolishes slavery, the last northern state to do so.
February 16
World Event
U.S. Navy Officer Stephen Decatur leads an attack to destroy the captured American frigate Philadelphia in Tripoli Bay. British Lord Nelson describes it as "the most daring act of the age."
February 21
World Event
Richard Trevithick successfully demonstrates his steam locomotive in Wales.
March 21
World Event
The French civil code, the "Code Napoleon," is adopted and the Duc d'Enghien is assassinated.
April 17
Event in Jefferson's Life
Jefferson's daughter Maria Jefferson Eppes dies at age 25.
May 14
Expedition Event
The "Corps of Volunteers for North West Discovery" sets off and heads up the Missouri in the big keelboat and two smaller pirogues.
May 18
World Event
Napoleon Bonaparte is declared emperor by the French Senate.
May 25
Expedition Event
The party passes La Charette, the westernmost white settlement on the Missouri.
June 15
World Event
The 12th Amendment to the Constitution, requiring electors to vote separately for president and vice president, is ratified.
June 16
Expedition Event
The Expedition reaches the mouth of the Kansas River.
June 29
Expedition Event
Expedition members John Collins and Hugh Hall are court-martialed and found guilty of being drunk on duty.
July 4
World Event
American author Nathaniel Hawthorne is born.
July 11
Event in Jefferson's Life
Vice President Aaron Burr shoots Alexander Hamilton in a pistol duel at Weehawken, N.J. Hamilton dies the next day.
August 3
Expedition Event
Lewis and Clark hold their first council with Indians. They meet with a group of Oto and Missouri chiefs near present- day Council Bluffs, Iowa. They hand out peace medals and other gifts, and Lewis delivers a speech.
August 20
Expedition Event
Sergeant Charles Floyd dies, probably from a burst appendix, and is buried near present-day Sioux City, Iowa.
August 30
Expedition Event
A council is held with the Yankton Sioux near present-day Yankton, S.D.
September 25
Expedition Event
Near present-day Pierre, S.D., the Teton Sioux demand payment of a toll from the expedition. A threatened fight is averted.
October 26
Expedition Event
The Expedition arrives at the earth-lodge villages of the Mandan and Hidatsa tribes, near present-day Bismarck, North Dakota. With 4,500 inhabitants, the villages have a greater population than St. Louis.
November 2-3
Expedition Event
Lewis and Clark select a site across the Missouri River from the Indian villages and begin construction of Fort Mandan.
November 4
Expedition Event
Toussaint Charbonneau, a French-Canadian trapper living with the Hidatsas, is hired to be an interpreter for the Expedition.
December 2
World Event
Pope crowns Napoleon emperor.
December 5
Event in Jefferson's Life
Jefferson is re-elected president, with 162 electoral votes to 14 for Charles Pinckney.
December 12
World Event
Spain declares war on England.
January 11, 1805
World Event
The Michigan Territory is organized.
February 11
Expedition Event
Sacagawea, Charbonneau's Indian wife, gives birth to a son, Jean Baptiste, at Fort Mandan. The child is later nicknamed Pompy, or Pomp by Clark.
March 4
Event in Jefferson's Life
Jefferson is inaugurated as president for a second term. George Clinton is vice president.
April 2
World Event
Danish author Hans Christian Andersen is born.
April 7
Expedition Event
Lewis and Clark send the keelboat down the Missouri River with a shipment for President Jefferson. The "permanent party" of the Expedition (consisting of Lewis, Clark, 27 soldiers, York, Charbonneau, Sacagawea, and her infant son) departs Fort Mandan.
World Event
Beethoven's 3rd Symphony ("Eroica") premieres.
April 27
World Event
U.S. Marines attack and capture the city of Derna on the shores of Tripoli.
May 1
World Event
Virginia passes a law requiring all freed slaves to leave the state.
May 26
Expedition Event
Lewis sees the Rocky Mountains for the first time.
June 4
World Event
The United States and Tripoli sign a peace treaty, ending their Mediterranean naval war.
June 13
Expedition Event
Lewis, scouting ahead of the main party, encounters the Great Falls of the Missouri River.
June 17
Expedition Event
The Expedition begins to prepare for the difficult, 18-mile portage around the Great Falls, a series of five waterfalls.
Late July
Expedition Event
The expedition reaches the Three Forks of the Missouri and heads southwest, up a stream they name the Jefferson River.
July 29
World Event
French historian Alexis de Tocqueville is born.
August 3
World Event
Mehmet Ali becomes ruler of Egypt.
August 8
Expedition Event
Sacagawea recognizes a land feature and tells the explorers they are close to the summer home of the Shoshone people.
August 9
World Event
Austria joins Britain, Russia, and Sweden in an alliance against France.
August 12
Expedition Event
Lewis ascends the Lemhi Pass and looks west from the summit, only to see more mountains.
Event in Jefferson's Life
The shipment from Fort Mandan arrives at the President's House in Washington.
August 17
Expedition Event
Sacagawea is reunited with her brother, the Shoshone chief Cameahwait, and helps negotiate for horses needed by the Expedition to cross the Rocky Mountains.
August 31
Expedition Event
With 29 horses, one mule, and a Shoshone guide, the expedition sets off overland.
September 9
Expedition Event
The explorers set up a camp they call Travelers Rest, near today's Lolo, Montana.
September 11
Expedition Event
The Expedition ascends into the Bitterroot Mountains, with Shoshone guide Old Toby leading the way.
October 7
Expedition Event
The Expedition heads down the Clearwater River.
October 16
Expedition Event
The Expedition enters the Columbia River.
October 21
World Event
French forces defeated by British under Admiral Nelson at Trafalgar.
November 7
Expedition Event
Clark writes in his journal that the Expedition is within sight of the ocean. Actually, the explorers are still 20 miles from the Pacific coast.
November- December
Expedition Event
A vote is taken on November 24 on where to spend the winter. Every member of the party participates, including Sacagawea and York. The explorers set up their winter encampment, Fort Clatsop, south of the Columbia River.
December 2
World Event
Napoleon's army defeats a Russian and Austrian force in the Battle of Austerlitz. Austria and Russia sue for peace.
December 23
World Event
Joseph Smith, founder of the Church of Jesus Christ of Latter-Day Saints, is born.
January 4, 1806
Expedition Event
In Washington, Jefferson welcomes a delegation of Missouri, Oto, Arikara, and Yankton Sioux chiefs who had met Lewis and Clark more than a year earlier.
January 8
Expedition Event
Members of the expedition view the skeleton of a beached whale on the Oregon coast.
March 6
World Event
English poet Elizabeth Barrett Browning is born.
March 23
Expedition Event
The Expedition leaves Fort Clatsop and begins its homeward journey. They give the Fort to Coboway, a Clatsop chief.
April 27
Expedition Event
The Walla Walla Indians invite the expedition to stay with them.
April 30
World Event
Robert Livingston and James Monroe conclude a treaty in Paris in which the United States purchases the 827,000-square-mile Louisiana territory from France for $15 million.
May 9
Expedition Event
The Nez Perce return 21 horses to the expedition, having cared for them over the winter.
May - June
Expedition Event
The party must wait until the snow melts on the Bitterroots before they can cross them.
June 8
Event in Jefferson's Life
George Wythe, Jefferson's law mentor and oldest friend, dies at age 80.
June 24
Expedition Event
The Expedition sets out to cross the Bitterroots with three Nez Perce guides.
July 3
Expedition Event
Lewis and Clark divide the men in order to explore more of the territory and to look for an easier pass over the Rockies. Lewis follows the Missouri River and Clark follows the Yellowstone River.
July 15
World Event
Lt. Zebulon Pike begins his western expedition from Fort Belle Fontaine, near St. Louis.
July 25
Expedition Event
Clark names a large rock pillar on the Yellowstone River Pompy's Tower (now Pompy's Pillar) after Sacagawea's son. Clark inscribes his name and the date. Still visible today, this is the only physical evidence of the Expedition's journey. At Camp Disappointment, Lewis tries to take solar readings, but it is too overcast and rainy.
July 27
Expedition Event
Lewis and his party have a skirmish with eight Blackfeet warriors in which two of the Indians are killed. These are the only violent deaths during the journey.
August 6
World Event
The Holy Roman Empire ceases to exist as Emperor Francis I abdicates.
August 12
Expedition Event
The explorers are reunited near the junction of the Missouri and Yellowstone Rivers.
August 14
Expedition Event
The party reaches the Mandan villages; Charbonneau, Sacagawea and Jean Baptiste leave the expedition.
September 23
Expedition Event
The Expedition arrives in St. Louis. Lewis writes to Thomas Jefferson that the corps has "penetrated the Continent of North America to the Pacific Ocean."
October 14
World Event
French forces under Napoleon defeat Prussians at Jena.
-Monticello Research Staff, 2002
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