William Clark and Meriwether Lewis were two leaders of the first United States expedition set by the American president Tomas Jefferson. The expedition had a purpose of finding and exploring possible water passages suitable for trade and commerce. The proclaimed goals of expedition were to find the Great Northwest Passage, and route to Pacific Ocean.
It was also a way of claiming sovereignty over a newly purchased territory as it was agreed in the Louisiana Purchase in 1803.
The expedition dubbed "Corps of Discovery" was commissioned by the president Tomas Jefferson in the purpose of claiming U.S. sovereignty over the native tribes along the River Missouri.
U.S. Army Captain Meriwether Lewis was named its leader and he chose William Clark as his companion. The company consisted of 33 men including 29 participants in the training.
Meriwether left on May 14, 1804, from Camp Dubois, Illinois and met up with Lewis in Saint Charles, Missouri, a short time later; the corps followed the Missouri River westward.
The expedition followed the Missouri river through what is now Kansas City, Missouri, and Omaha, Nebraska.
Soon, one of the expeditioners died, quartermaster Charles Floyd, apparently from an acute appendicitis. He was buried at Floyd's Bluff, and he was the only victim that the expedition suffered.
After a bad start, the expedition reached The Great Planes, a place abundant with elk, deer, bison, and beavers.
Thanks to relations that the expedition established with several dozen indigenous tribes, they avoided starvation and getting lost in the Rocky Mountains.
They traveled equipped with the goods to trade and even had silver medals that Jefferson had commissioned to be made in the sole purpose to be given away to the natives as a token of a good will.
Not all the tribes were friendly towards the Corps. There were issues regarding a stolen horse that Lacote Sioux tribe was accused for. Two sides were at a brink of confrontation but sides finally backed down and the expedition continued on to Arikara territory.
The company camped for the winter in the Mandan nation's territory. Here they met a French-Canadian fur trapper named Toussaint Charbonneau, and his young Shoshone wife, Sakakawea, or Sacajawea.
They hired him to be an interpreter and he took his wife along with him. Soon it would be proven that she was much more worth asset to the expedition than anyone imagined.
The expedition continued westward following the River Missouri. Traveling by horses, boats and canoes they came to the river headwaters. They came to Continental Divide at Lemhi Pass and traveled onwards, crossing the Clearwater River, Snake River and finally the Columbia River where they decided to build Fort Clatsop and stay for the winter.
The expedition reached the Pacific Ocean in November of 1805.
The party turned home on March 23, 1806. They split up into two groups on July 3, 1806 after crossing the Continental Divide so that Lewis could explore the Marias River while Clark went south and they met again when they reached the Yellowstone and Missouri Rivers on August 11.
Lewis and Clark drew more than 140 maps of the area and were the first 'official' Americans that described this part of the newly acquired territory.
Sacagawea separated with the expedition at Fort Mandan and on September 23, Lewis and Clark reached St. Louis were they were welcomed as national heroes.