Deeply interested in the West, President Thomas Jefferson appropriated $2,500 from Congress in 1803 for what would become known as the Lewis and Clark Expedition.
Captains Meriwether Lewis and William Clark were the co-leaders of the famous expedition, which lasted from May 1804 until September 1806. Their efforts would open the Pacific Northwest to settlement and economic progress.
The expedition spent nine days in what is now Clark County, camping near Washougal, Ridgefield, and the present Port of Vancouver. On March 30, 1806, while camped southeast of Vancouver Lake, Lewis wrote about the fertile soil in the area and concluded that the valley was "capable of supporting 40,000 to 50,000 souls and indeed the only desirable situation for a settlement on the western side of the Rocky Mountains."
When Lewis and Clark returned to the Mandan Indian villages in North Dakota on their way home, they met two American fur trappers. These and other "mountain men" would explore and map the west from 1806 to the early 1840s.