Final answer:
The Lewis and Clark expedition was significant because it provided the first formal mapping of the western lands following the Louisiana Purchase, contributing to U.S. geographical knowledge and territorial claims.
Step-by-step explanation:
The journey of Lewis and Clark was remarkable because the land they charted had never before been formally mapped. President Thomas Jefferson tasked Meriwether Lewis and William Clark with leading an expedition to explore and map the territory acquired from the Louisiana Purchase, in search of commercial possibilities and potential trade routes. The expedition, known as the Corps of Discovery, took place from 1804 to 1806. Although they did not find an all-water route to the Pacific Ocean, they collected crucial geographical data and established relationships with various Native American tribes. This groundwork laid the foundation for future United States claims and expansion into the Pacific Northwest.
Despite many challenges, including fierce storms and encounters with wildlife, the explorers collected hundreds of plant and animal specimens and created detailed maps and notes documenting their journey. The expedition ultimately increased geographical knowledge of the West and strengthened the United States' territorial claims.