Lewis collected the gumbo evening primrose (Oenothera caespitosa) near the Great Falls.

The Great Falls of the Missouri

On June 13, 1805, Lewis arrived at the waterfalls the Hidatsa had told him about. He heard "a roaring too tremendous to be mistaken for any cause short of the great falls of the Missouri…. I took my position on the top of some rocks about 20 feet high…. immediately at the cascade the river is about 300 yds. wide…. this truly magnifficent and sublimely grand object."

An 18.5 mile, month-long portage ensued. Enduring back-breaking work, hot summer sun, prickly pear cactus and troublesome mosquitoes, they completed their mammoth task and celebrated by empting the whiskey barrel on July 4, 1805.

Great Missouri Falls in 1867 from Records of the Office of the Chief Signal Officer – Signal Corps Photographs of American Military Activity. The Ryan Dam has since put the "Great Falls" underwater. Photographer is unknown. Source: NARA

The bushy-tailed woodrat caught Lewis' attention with its large nests…"in clifts of rocks and hollow trees… they feed very much on the fruit and seed of the prickly pear; or at least I have seen large quantities of the hulls of that fruit [prickly pear cactus] lying about their holes and in their nests."

The following are a few of the stops in the journey:

• White Cliffs
• Marias River
• Great Falls
• Headwaters of the Missouri
• Beaverhead Rock
• Travelers' Rest Westbound
• The Rocky Mountains
• Travelers' Rest Eastbound
• Return Across Montana
• The Voyage's End