464 pages
Illus., maps
In April 1805 Lewis and Clark and their party set out from Fort Mandan following the Missouri River westward. This volume recounts their travels through country never before explored by white people. With new personnel, including the Shoshone Indian woman Sacagawea, her husband Toussaint Charbonneau, and their baby, nicknamed Pomp, the party spent the rest of the spring and early summer toiling up the Missouri. Along the way they portaged the difficult Great Falls, encountered grizzly bears, cataloged new species of plants and animals, and mapped rivers and streams.