Which expedition, commissioned by Thomas Jefferson in 1803, explored the newly acquired Louisiana Territory?

The Lewis and Clark Expedition explored the newly acquired Louisiana Territory from 1804 to 1806.

Thomas Jefferson selected Meriwether Lewis to lead the mission, and Lewis chose William Clark as co-leader. Their official goals included mapping the territory, finding a practical route to the Pacific, studying plants and animals, and establishing diplomatic relations with Native nations.

The Corps of Discovery departed near St. Louis in May 1804. The party traveled up the Missouri River, crossed the Rocky Mountains, followed the Columbia River, and reached the Pacific Ocean before returning.

The expedition did not discover an all-water Northwest Passage, but it greatly expanded U.S. geographic knowledge. Sacagawea, a Shoshone woman, traveled with the group and helped communicate and negotiate during parts of the journey.