Bitterroot Mountains

The Bitterroot Mountains are a small spur range of the Rocky Mountains; they run along the border of Montana and Idaho. The mountains were the area of Lewis and Clark's crossing of the Rocky Mountains and provided the most difficult terrain encountered by the expedition. The lack of game or other food, the lack of forage, and the rocky, freezing terrain made both the east-to-west and the return west-to-east passages miserable and dangerous.

Columbia River

The major drainage route of the Northwest United States and British Columbia, the Columbia is the largest river flowing into the Pacific Ocean from the Western Hemisphere. The Columbia River was one of the principle destinations of the Lewis and Clark Expedition and forms the setting of about one third of the novel.

Continental Divide

A theoretical line along elevated terrain which forms the border between the two great watersheds of...