A Nation Glimpsed at the Edge of the Plains
Of all the Native nations encountered by the Corps of Discovery, the Blackfeet — and specifically the Piegan (Pikuni) division — occupy a singular and troubling place in the journal record. They are the only Indigenous people with whom the expedition shed blood, and their shadow falls across the upper Missouri narrative long before the encounter itself takes place. The journals provided here yield only a handful of direct references, but those references frame the most dangerous chapter of the return journey.
Anticipation in the Upper Missouri Country
As the party ascended the Missouri in May 1805, Clark’s daily entries describe a landscape they understood to be Blackfeet hunting territory, even when he does not name them. On May 16, 1805, Clark catalogues a country of broken hills, scattered pine and cedar, and abundant buffalo and deer; on May 17, 1805, he notes the saline crusts on the bluffs and the brackish creeks; and on May 30, 1805, he records cold rain, snow on the high country, and treeless plains. These are the geographic preludes to Blackfeet country. The captains had been warned by the Hidatsa and Shoshone that this region belonged to a powerful, well-armed people who traded with British posts to the north — a reputation that conditioned every later decision on the Marias.
The Marias Reconnaissance
On July 17, 1806, during the homeward split of the party, Lewis pushed northwest from the Great Falls toward the Marias River with a tiny detachment, hoping to determine whether that drainage reached as far north as the 50th parallel — a finding that would extend American claims under the Louisiana Purchase. He describes the country with unease as well as wonder:
“I steered my course through the wide and level plains which have somewhat the appearance of an ocean, not a tree nor a shrub to be seen… the whole face of the country as far as the eye can reach looks like a well shaved bowlinggreen, in which immence and numerous herds of buffaloe were seen feeding attended by their scarcely less numerous sheepherds the wolves.”
The openness of this terrain — beautiful, gameful, but offering no cover — would matter a few days later.
Signs of Watching Eyes
Far to the south, Clark’s detachment on the Yellowstone was experiencing what was almost certainly the work of the same nation, though Clark could not be certain. On July 23, 1806, he reported that horses had been stolen on the night of July 10, and that fresh sign had appeared again:
“Sergt. Pryor found an Indian Mockerson and a Small piece of a roab, the mockerson worn out on the bottom & yet wet, and have every appearance of haveing been worn but a fiew hours before. those Indian Signs is Conclusive with me that they have taken the 24 horses which we lost on the night of the 10th instant.”
Clark does not assign the theft to the Blackfeet by name in this entry, but later interpretation — and the geography — has long associated these losses with Blackfeet or allied raiders operating south of their core range.
The Fight on the Two Medicine
The decisive encounter is summarized in the editorial entry for July 27, 1806. Lewis’s party of four met eight Piegan Blackfeet on the plains, smoked with them, and camped together. At dawn the warriors attempted to seize the expedition’s rifles and drive off the horses. Lewis’s own words, as preserved in the summary, capture the moment:
“I sliped behind a rock and spoke to the effect that I would shoot them if they did not give back my horse.”
In the struggle that followed, Reubin Field stabbed one warrior to death and Lewis shot another. The editorial note frames the historical weight precisely:
“This was the only violent death caused by the expedition during its entire journey.”
Lewis’s party then made a punishing forced ride — over 100 miles in 24 hours — back to the Missouri, fearing a retaliatory pursuit that, so far as the journals record, never materialized in arms but would echo for decades in Blackfeet hostility toward American trappers on the upper Missouri.
Aftermath and Apprehension
The fear of Blackfeet retaliation lingered in the men’s nerves. On August 11, 1806, when Pierre Cruzatte accidentally shot Lewis during an elk hunt, the captain’s first thought was that Blackfeet warriors had caught up with him:
“I instantly supposed that Cruzatte had shot me in mistake for an Elk as I was dressed in brown leather.”
That a senior officer’s reflex assumption was a Blackfeet ambush — hundreds of river miles below the Marias — is itself a measure of how heavily the July encounter weighed on the party. Clark’s entry of August 12, 1806 records the relief and dismay of the reunion: “I was alarmed on the landing of the Canoes to be informed that Capt. Lewis was wounded by an acc[ident].”
The Reach of Blackfeet Power
The journals also testify, indirectly, to how far Blackfeet raiding extended. On August 14, 1806, as Clark approached the Hidatsa villages on the return, he met the principal chief of the Little Village of the Minetarees:
“the Chief of the little Village of the Menetarias cried most imoderately, I enquired the Cause and was informed it was for the loss of his Son who had been killed latterly by the Blackfoot Indians.”
For the Hidatsa as for the Corps, the Blackfeet were a northern force whose raids could carry grief deep into the Missouri valley.
What the Journals Do Not Say
Within these entries, the captains record almost nothing of Blackfeet society from observation: no village visits, no councils, no ethnographic description of the kind they lavished on the Mandan, Shoshone, or Nez Perce. What they knew, they knew secondhand — from Hidatsa informants, from Shoshone fears, and from the brief, doomed parley on the Two Medicine. The Blackfeet enter the record primarily as a strategic presence: a people whose territory had to be skirted, whose horses were coveted, whose retaliation was dreaded, and whose warriors, when finally met face to face, fought to defend property the expedition refused to surrender.
A Lasting Consequence
The editorial summary for July 27 closes with a sober assessment: “This encounter had lasting consequences for American relations with the Blackfeet, who remained hostile to American traders and trappers for decades.” The journals themselves do not — and cannot — narrate that long aftermath. But within their pages, the Blackfeet stand as the one nation the Corps of Discovery could not befriend, could not parley with successfully, and could not avoid leaving a wound upon. The sources here are sparse, and any fuller portrait of Blackfeet life in 1805–1806 must come from outside the expedition’s record.
