To identify the natural resources of the lands.To map the lands covered by the Lewis and Clark Expedition.To study and document plants, animals, birds, geology and the geography of the lands.Explore the lands obtained in the Louisiana Purchase.The goals and purpose of the Lewis and Clark Expedition was to: What were the goals and the purpose of the Lewis and Clark Expedition? The purpose, aims and goals of the Lewis and Clark Expedition and the Corps of Discovery were both scientific and commercial. Lewis and Clark Expedition: The Goals and Purpose of the Lewis and Clark Expedition One of the important events during his presidency was the Lewis and Clark Expedition that followed the 1803 Louisiana Purchase. Thomas Jefferson was the 3rd American President who served in office from Mato March 4, 1809. The Lewis and Clark Expedition started on and ended on September 23, 1806. Louis to the mouth of the Columbia River. The Lewis and Clark Expedition traveled along the Missouri River from St. They were helped by a female Shoshone guide called Sacajawea. The purpose of the expedition was both scientific (creating maps and documenting plants and animals) and commercial (establishing trade and identifying natural resources). Summary: The Lewis and Clark Expedition consisted of a select group of military men, called the Corps of Discovery and civilians, led by Captain Meriwether Lewis and Second Lieutenant William Clark to explore the US lands obtained in the 1803 Louisiana Purchase and the Pacific Northwest.