Lewis & Clark's Route: Mapping the Corps of Discovery Across Western North America

The Lewis and Clark Expedition (1804–1806) traversed the newly acquired Louisiana Purchase and beyond, mapping a path from the Mississippi to the Pacific.

Route Overview (Modern States Crossed)

1. Missouri: Departed St. Louis (Camp Dubois) May 1804
2. Kansas / Iowa (brief): Missouri River border
3. Nebraska: Up the Missouri, Council Bluffs area
4. South Dakota: Pierre, meeting with Teton Sioux
5. North Dakota: Fort Mandan (winter 1804–05), met Sakakawea
6. Montana: Great Falls portage (18 miles, 3 weeks), Marias River, Gates of the Mountains
7. Idaho: Lemhi Pass (Continental Divide), Bitterroot Mountains (near disaster), Nez Perce rescue
8. Washington: Snake River, Columbia River to Pacific
9. Oregon: Fort Clatsop (winter 1805–06), Pacific coast, salt works

Key Geographic Milestones

• Missouri River: Primary highway — 2,300+ miles upstream
• Rocky Mountains: Crossed at Lemhi Pass (7,373 ft) — no Northwest Passage
• Bitterroot Range: Most grueling segment — starvation, cold, 11 days
• Columbia River: Final water route to ocean
• Pacific Ocean: Reached Nov 1805 — "Ocian in view! O! the joy"

Indigenous Nations Encountered

Contacted ~50 tribes: Otoe, Missouri, Yankton Sioux, Teton Sioux, Arikara, Mandan, Hidatsa, Shoshone, Nez Perce, Chinook, Clatsop, etc. Essential assistance: horses, food, guides, geographic knowledge, diplomacy.

Return Journey (1806)

Split parties: Lewis → Marias River (Blackfeet encounter); Clark → Yellowstone (Pompey's Pillar signature). Reunited in ND, returned to St. Louis Sept 1806.

Legacy

• Mapped ~8,000 miles, 140 maps, 178 plant / 122 animal specimens
• Established U.S. claim to Oregon Country
• Foundation for fur trade, westward expansion, scientific knowledge

The expedition didn't just cross the West—it invented the American West in the national imagination.