Meriwether Lewis must have been exultant on August 11, 1806. After 28
months, the expedition—an ambitious venture to explore the western part
of the continent, proposed by President Thomas Jefferson—was nearly
over. Lewis, his cocaptain William Clark, and a pack of grizzled woodsmen
had struggled up the Missouri River, wintered in North Dakota, crossed the
Rockies, wintered again on the Oregon coast, and backtracked across the mountains.
On that day, Lewis awaited Clark and a small party after taking the
main group down the Yellowstone River. Once reunited, an easy 3-week float
would land them in St Louis as heroes.
Vastag B. Medicine on the Lewis and Clark Trail. JAMA. 2003;289(10):1227-1230. doi:10.1001/jama.289.10.1227