When President Thomas Jefferson committed to the Louisiana Purchase, he was buying a pig in a poke, not knowing exactly what was in the territory west of the Mississippi being purchased from France. Beginning 200 years ago this year, the 33-member Corps of Discovery, led by captains Meriwether Lewis and William Clark, began a two-year voyage of discovery to find out what existed in the then-unknown American West.

The corps traveled from Pittsburgh, Pa., to Fort Clatsop, Oregon, and back, but spent much of their time in what is now North Dakota, outlasting the winter of 1804-05 at Fort Mandan.