The Lewis and Clark expedition

United States expedition to the Pacific Coast.
It was sent

by President Thomas Jefferson and led by Meriwether Lewis and William Clark.
Their objects were both scientific and commercial - to study the area's plants, animal life, and geography, and to discover how the region could be exploited economically.
Jefferson placed special importance on declaring U.S. sovereignty over the Native American tribes along the Missouri River, and getting information about the resources in the recently-completed Louisiana Purchase.

woman, Sacagawea, the slave wife of a French-Canadian fur trader.
Her

son was born in 1805 with the help of the expedition.
She served as an interpreter.

the 1803–1804 Camp Dubois winter staging area in Illinois Territory.
They

left on May 14, 1804.
The ships followed the Missouri River westward.

the Missouri River.

During the final week of August, Lewis

and Clark reached the edge of the Great Plains.

indigenous nations.

Without their help, the expedition would have starved to

death or become hopelessly lost in the Rocky Mountains.

The expedition recorded more than 200 plants and animals that

were new to science and noted at least 72 native tribes.
In 1807 Patrick Gass published a book of the journey.

American land, for science and for establishing relations with different

tribes.