Which explorer-led expedition across the western United States (1804-1806) provided detailed information about the Louisiana Purchase region?

• A. The Coronado Expedition.
• B. The Journeys of Lewis and Clark in 1770.
• C. The Lewis and Clark Expedition.
• D. The Bonneville Expedition.

Answer: (C)

The question is asking which expedition produced the most detailed, firsthand description of the Louisiana Purchase region. The Lewis and Clark Expedition, carried out from 1804 to 1806, was specifically sent to explore and map the newly acquired territory. They journeyed from St. Louis to the Pacific, gathering extensive observations on geography, climate, plants, animals, natural resources, and the Native American peoples they encountered, and they kept thorough journals and produced maps that became the main source of knowledge about that region at the time. That focused purpose and rich documentation make it the best answer. Other choices don’t fit: the Coronado Expedition explored the Southwest many years earlier; a Lewis and Clark journey in 1770 didn’t happen; and the Bonneville Expedition occurred later, covering different western areas.