The Lewis and Clark Expedition brought back useful information gathered from the newly acquired Louisiana Territories. Who was US president during this famous expedition?

After purchasing the Louisiana Territories from France, President Thomas Jefferson commissioned Meriwether Lewis and William Clark to lead a group of army volunteers to explore the newly acquired land. The main objectives were to explore and map the territory, find a route across the Western part of the continent, and establish an American presence in this territory before other European powers tried to claim it. The adventure was considered a success and lasted from May 1804 to September 1806.