Final answer:
Sacagawea was the Shoshone woman who assisted Lewis and Clark on their expedition of the Louisiana Purchase. Her roles as an interpreter and peaceful presence were vital, though she did not serve as a guide in the typical sense of the word. President Jefferson tasked the Corps of Discovery with exploring and mapping the new territory, potentially establishing an all-water route to the Pacific.
Step-by-step explanation:
The Shoshone woman who provided language skills and knowledge of geography to help Lewis and Clark during their expedition of the Louisiana Purchase was Sacagawea. She played a key role as an interpreter and as a figure of peace that indicated the Corps of Discovery was not a war party. On the journey, she was accompanied by her husband Toussaint Charbonneau and their newborn son, and while her contributions to the expedition were significant, especially in relations with native tribes, she was not a guide in the strictest sense and largely did not retain detailed memories of the landscapes from her childhood due to having been kidnapped at a young age.
President Thomas Jefferson initiated the Corps of Discovery, led by Captain Meriwether Lewis and Lieutenant William Clark, to explore the newly acquired Louisiana Territory, map the land, establish trade, and strengthen U.S claims to the Pacific Northwest. The expedition lasted from 1804 to 1806 and their journey through the Missouri River to see if an all-water route to the Pacific could be found was a cornerstone of American expansion.