Of Welsh descent, Meriwether Lewis (1774-1809) was an American explorer, soldier, politician, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition, also known as the Corps of Discovery, with William Clark. Their mission was to explore the territory of the Louisiana Purchase, establish trade with, and sovereignty over the natives near the Missouri River, and claim the Pacific Northwest and Oregon Country for the United States before European nations. They also collected scientific data and information on indigenous nations.

Lewis was born in Virginia and had no formal education until he was 13 years old, but during his time in Georgia, he enhanced his skills as a hunter and an outdoorsman. He joined the Virginia militia, and in 1794 he was sent as part of a detachment that was involved in putting down the Whiskey Rebellion. In 1795, Lewis joined the United States Army and rose to the rank of captain.

Lewis was appointed as Secretary to the President by President Thomas Jefferson in 1801, and when Jefferson began to plan for an expedition across the continent, he chose Lewis to lead the expedition. After the Louisiana Purchase in 1803, the two-year exploration by Lewis and Clark was the first transcontinental expedition to the Pacific Coast by the United States.

After returning from the expedition, Lewis received a reward of 1,600 acres of land. He also initially made arrangements to publish the Corps of Discovery journals, but had difficulty completing his writing. In 1807, Jefferson appointed him governor of the Louisiana Territory, where he published the first laws and established roads. However, his record as an administrator was mixed, and he died in 1809 from gunshot wounds in what was either a murder or suicide.