Section 1: Introduction
President Thomas Jefferson, the nation’s third President, had a goal of expanding the United States so that it would stretch all the way from the Atlantic Ocean to the Pacific Ocean. Many people at that time believed that there were rivers connecting the ocean on the East Coast to the ocean on the West Coast. President Jefferson thought that it was important to claim the land along these rivers to give the United States an advantage over other nations in shipping and trading. Before the land could be claimed, however, it had to be explored.
After the purchase of Louisiana in 1803, President Jefferson hired a group of adventurers to explore the new land and also to find a river leading to the Pacific Ocean. The journey taken by these explorers has been called “The Greatest Adventure in American History.” This great adventure was the Lewis and Clark Expedition.