Key Dates of the Lewis and Clark Expedition
The Lewis and Clark expedition (at the time known as the Corps of Discovery Expedition), was the first American exploration of what is now the western portion of the United States. Lewis and Clark departing from St. Louis, Missouri, in 1804 and went all the way to the Pacific coast.
January 18, 1803
Thomas Jefferson sends a secret communication to Congress seeking authorization for the expedition. A $2,500 appropriation is requested.
Napoleon offers to sell the Louisiana Territory to United States.
Meriwether Lewis, chosen as commander of the expedition, goes to Philadelphia to study botany, zoology, medicine, and celestial navigation with the nation’s leading scientists.
Lewis invites William Clark to share command of expedition, and Clark accepts.
July 4–5, 1803
The Louisiana Purchase (for $15 million) is announced, adding 828,000 square miles to the United States and nearly doubling the current size of the country.
Lewis leaves Washington for Pittsburgh to oversee construction of a keelboat.
Lewis purchases a Newfoundland dog for $20 to take on the expedition.
Lewis takes the keelboat down the Ohio River, stopping at Falls of the Ohio to pick up Clark and nine recruits.
Lewis and Clark proceed down the Ohio River from Clarksville, Indiana, with his recruits and with York, Clark’s slave since childhood.
Lewis and Clark establish Camp Dubois (also known as Camp Wood) for the winter on the east bank of the Mississippi River, where they recruit and train more men.
March 10, 1804
Lewis and Clark attend ceremonies in St. Louis that celebrate the transfer of the upper Louisiana Territory from France to the United States.
May 14, 1804
Clark and the expedition set out from Camp Dubois for St. Charles, Missouri.
May 21, 1804
Lewis and a small company leave on horseback from St. Louis, bound for St. Charles.
The expedition marks the nation’s first Independence Day celebration west of the Mississippi near today’s Atkinson, Kansas.
Private Alexander Willard is court-martialed for falling asleep on duty and is sentenced to four sets of 100 lashes.
August 3, 1804
The expedition holds its first meeting and council with western Indians, the Oto and Missouri.
August 20, 1804
Near today’s Sioux City, Iowa, Sergeant Charles Floyd dies, probably from a ruptured appendix.
August 30, 1804
The expedition holds friendly council with Yankton Sioux near today’s Yankton, South Dakota.
September 25, 1804
A stand-off between Teton Sioux and the expedition ensues after the tribe demands a toll to proceed upriver. Leader Black Buffalo defuses the tension.
October 24, 1804
The expedition reaches Mandan and Hidatsa villages. Lewis and Clark decide to build their second winter fort across from the main Mandan village, about 50 miles north of today’s Bismarck, North Dakota.
November 4, 1804
Lewis and Clark hire Toussaint Charbonneau, French-Canadian fur trader, as interpreter. He brings along Sacagawea, one of his wives and a teenage mother-to-be who is a Shoshone living with the Hidatsa.
February 11, 1805
Sacagawea gives birth to a baby boy, Jean Baptiste, with Lewis assisting the delivery.
April 7, 1805
The big keelboat and ten men are sent back downriver, along with plant and animal specimens, maps, reports, and Indian artifacts destined for President Jefferson.
The permanent party, including Sacagawea and her baby, resume the westward voyage in two pirogues (flat-bottomed wooden boats) and six dugout canoes.
April 29, 1805
In today’s eastern Montana, the Corps is dumbfounded by the abundance of wildlife, including buffalo herds that number tens of thousands of animals.
The Corps encounters its first grizzly bear, a species unknown to early Americans.
May 3, 1805
The expedition reaches the White Cliffs of the Missouri River, near today’s Big Sandy, Montana, and described as “seens of visionary inchantment.”
June 13, 1805
Lewis arrives at the Great Falls of the Missouri, the “grandest sight [he] ever beheld.” It takes a month to portage around these falls.
Late July 1805
The expedition reaches the headwaters (the official start) of the Missouri River. Sacagawea recognizes the place where she was captured by the Hidatsas five years earlier.
August 12, 1805
The shipment to Jefferson arrives in Washington, D.C.
Lewis climbs to Lemhi Pass, on what is now the Idaho-Montana border. He expects to see a plain and a river on the other side of the summit, but instead he finds nothing but more mountains.
August 17, 1805
Lewis finds the Shoshone tribe and negotiates for horses. The Shoshone leader, Cameahwait, turns out to be Sacagawea’s brother. The spot is named Camp Fortunate.
August 31, 1805
The expedition leaves the Shoshones and heads north toward the Bitterroot Mountains, guided by a Shoshone that Lewis and Clark call Old Toby.
September 11–22, 1805
The expedition ascends into the Bitterroot Mountains in what is now the panhandle of Idaho, traveling for 11 days and nearly starving before emerging in the territory of the Nez Perce Native Americans.
Late September 1805
On the advice of an elderly Nez Perce woman named Watkuweis, the Nez Perce decide to befriend and not kill the Corps.
October 7, 1805
In five canoes that they build under the guidance of the Nez Perce, the expedition pushes off downstream on the Clearwater River.
October 16, 1805
The expedition reaches the Columbia River, which is teeming with salmon.
November 7, 1805
Twenty miles from the Pacific Ocean, Clark writes “Ocian in View! O! the Joy.”
November 24, 1805
The Corps of Discovery, including Sacagawea and York, vote on where to spend the winter. The majority decide to build a fort on the south side of the Columbia.
As a winter camp, the Corps members build Fort Clatsop (named after the local tribe) that sits near today’s Astoria, Oregon.
January 4, 1806
In Washington, D.C., Jefferson welcomes a delegation of Missouri, Oto, Arikara, and Yankton Sioux leaders.
March 23, 1806
The Corps presents Fort Clatsop to the Clatsop leader, Coboway, and they set out for home.
May–late June 1806
The expedition waits in Nez Perce country for the snow to melt in the Bitterroot Mountains before trying to cross.
July 3, 1806
The expedition splits into two groups, Clark taking a group down the Yellowstone and Lewis heading to Great Falls and the northernmost reaches of the Marias River.
July 25, 1806
Clark names a sandstone hill on the Yellowstone River “Pompy’s Tower” after Sacagawea’s son’s nickname, and Clark inscribes his name and the date on it. This is now the site of Pompey’s Pillar National Monument in central Montana.
July 26 and 27, 1806
Lewis and three men camp with some Blackfeet youths and in the morning, the Blackfeet attempt to take their horses and guns. In the fight that follows, two Blackfeet are killed.
August 12, 1806
The expedition is united on the Missouri downstream from the mouth of the Yellowstone River.
The expedition arrives back at the Mandan villages. Lewis and Clark say goodbye to Sacagawea, Jean Baptiste, and Charbonneau.
Early September 1806
Covering 70 miles a day, the expedition speeds through Teton Sioux country, stopping only to exchange some harsh words with the Native Americans who tried to block them on the trip westward.
September 20, 1806
The expedition cheers the sight of a cow and reaches La Charette.
September 23, 1806
The expedition reaches St. Louis completing a trek of two years, 4 months, 10 days.
October 11, 1809
Meriwether Lewis commits suicide at Grinder’s Stand, an inn south of Nashville, Tennessee.
December 20, 1812
Sacagawea dies at Fort Manuel, in today’s South Dakota.
Exact date unknown, 1832
York dies of cholera (it’s believed), having been free for approximately 15 years.
September 1, 1838
William Clark dies at the home of his eldest son, Meriwether Lewis Clark.