In 1805, the American Lewis and Clark expedition marked the first official American exploration of the area, then creating the first temporary settlement of Euro-Americans in the area near the mouth of the Columbia River at Fort Clatsop. Two years later in 1807, David Thompson of the British-owned North West Company (later the Hudson's Bay Company) penetrated the Oregon Country from the north, via Athabasca Pass, near the headwaters of the Columbia River. From there he navigated nearly the full length of the river through to the Pacific Ocean.