Lewis & Clark (1804-1806)
In 1803 President Thomas Jefferson purchased a large portion of land west of the Mississippi River from Napoleon I of France. It was land known as Louisiana and part of the French colony of New France, but became territory of the United States of America. After the purchase, President Jefferson commissioned Captains Meriwether Lewis and William Clark to explore not only the land purchased from France, but all the way up into the Pacific Northwest. Their expedition took them up the Missouri River across the Bitterroot Mountains and down the Columbia River to the Pacific Ocean. The Corps of Discovery (the name of Lewis and Clark's expedition team) set out from Missouri in 1804 and didn't return till 1806.