Which 1804 expedition explored the newly acquired Louisiana territory for the United States?

The Lewis and Clark Expedition explored the newly acquired Louisiana territory for the United States.

Led by Meriwether Lewis and William Clark, the expedition departed near St. Louis in May 1804 and returned in September 1806. President Thomas Jefferson instructed the explorers to study the geography, plants, animals, peoples, and possible routes across the continent.

The expedition traveled up the Missouri River, crossed the Rocky Mountains, and reached the Pacific Ocean near the mouth of the Columbia River. Sacagawea, a Lemhi Shoshone woman, joined the journey with her husband Toussaint Charbonneau and helped the party communicate and navigate in parts of the West.

The expedition did not discover an all-water passage across North America, but it mapped routes and gathered extensive information. Its work helped the federal government understand the scale and resources of the lands acquired from France.