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Lewis and Clark Expedition

Scholasticus K May 12, 2019
The expedition of Lewis and Clark helped the nascent United States of America expand into the west, towards the Pacific Ocean.
The western coast of the United States of America had never been properly or officially explored and charted before the 1800s. Thomas Jefferson had advocated the expansion of the United States towards the west.
Upon the purchase of the Louisiana territory from France, Congress approved President Jefferson's plan to organize an expedition into the northwestern wilderness, which was still an unexplored region.
The aim of this expedition was to chart the territory along the Missouri river. Jefferson wanted to establish a water route along the river towards the Pacific Ocean.
"The objective of your mission is to explore the Missouri river, and such principal streams of it, as, by its course and communication with the waters of the Pacific ocean,...
...whether the Columbia, Oregon, Colorado, or any other river may offer the most direct and practicable water communication across the continent, for the purposes of commerce", as written by President Thomas Jefferson to Captain Meriwether Lewis in a letter dated June 20, 1803.

Members of the Corps of Discovery

The expedition was named 'The Corps of Discovery'. The Corps of Discovery consisted of 30 members serving in the United States Army.


  • Meriwether Lewis
  • William Clark


  • Charles Floyd
  • Patric Gass
  • John Ordway
  • Nathaniel Pryor


  • William Bratton
  • John Collins
  • John Colter
  • Pierre Cruzatte
  • Joseph Field
  • Reuben Field
  • Robert Frazer
  • George Gibson
  • Silas Goodrich
  • Hugh Hall
  • Thomas Proctor Howard
  • Francis LaBiche
  • Jean Baptiste LePage
  • Hugh McNeal
  • John Potts
  • George Shannon
  • John Shields
  • John B. Thompson
  • Peter M. Weiser
  • William Werner
  • Joseph Whitehouse
  • Alexander Hamilton
  • Willard
  • Richard Windsor

Civil Members

  • Toussaint
  • Charbonneau
  • George Drouillard
  • Sacagawea
  • Jean Baptiste
  • York
  • Charbonneau
  • Baptiste Deschamps
  • Pierre Dorion
In addition to these members, a Newfoundland dog named Seaman was also a part of the expedition.


The expedition was planned by President Thomas Jefferson. On January 18, 1803, he proposed the plan of the expedition before the Congress, through a secret message. The Congress sanctioned a fund of $2,500 for the journey. In the spring of 1803, Meriwether Lewis was appointed as the leader of the expedition. He began to receive his training in Philadelphia.
The report of the successful purchase of Louisiana was communicated to the United States in July 1803. In summer, Lewis supervised the construction of the keel-boat, recruited all the other members of the expedition, and selected William Clark as his partner. The first winter camp, Camp Wood, was established on the banks of river Wood, near Illinois.
The actual journey of the Corps of Discovery began on May 14, 1804. The first meeting with the local American Indians was held on August 30,1804, with the Yankton Sioux tribe. There was interaction with the Mandan and Hidatsa tribes in their journey westwards.
On November 4, 1804, Canadian fur trader Toussaint Charbonneau and his wife Sacagawea joined the expedition as interpreters. The winter of 1804 was spent in Fort Mandan.
On April 7, 1805, a shipment of the collected facts and samples was sent to the President. On June 1, the expedition reached a point where the Missouri river forked. After a thirteen-day journey from the unmarked fork, Lewis reached the massive falls of Missouri.
The five enormous cascades were named as the Great Falls of Missouri. On September 11, the Corps of Discovery began crossing the Rocky mountains, an enterprise that lasted till September 23. The expedition reached the Pacific coast on November 24.
The return journey from the western coast of the Pacific ocean began on March 23, 1806, and ended on September 23, when the Corps of Discovery reached St. Louis.


During the course of the expedition, the members of Corps of Discovery maintained several personal journals, that proved very helpful for later expeditions in the region. The expedition mapped the unknown regions of the Northwest, and made about 140 maps.
The exact span and height of the Rocky mountains was also estimated by the expedition. It was earlier believed that the span of the Rocky mountains was rather short, and it would take only one day to cross them!
As the expedition was of a scientific nature, it also made many natural studies. During the course of the expedition, over 100 species of animals and 176 new plants were discovered. The most interesting discovery was that of the prairie dog, which was gifted to President Jefferson by the members of the expedition.
Over the course of the journey, the members also established very good relations with the Amerindians that proved helpful in the later years. Sacagawea, who acted as an interpreter, belonged to the Shoshone tribe.
Due to her presence, hostile tribes never posed any resistance, but instead welcomed them warmly. Lewis and Clark did not fully accomplish the task of setting up a channel of communication through the rivers, but they discovered a vast portion of the unexplored regions of the United States.
As writer James Ronda once wrote, "Lewis and Clark matter today because they act as a benchmark by which we can measure change and continuity in everything from the environment to relations between people."