An important portion of The Corps of Discovery’s journey occurred in southwest Montana. On July 19, 1805, Lewis and his men were struggling up the Missouri between present-day Upper and Lower Holter lakes. “from the singular appearance of this place I called it the gates of the rocky mountains.” The next day, searching for “the three forks of the Missouri,” they entered the first of southwest Montana’s big valleys – Helena’s Prickly Pear Valley.
Arriving at the meeting of the rivers on July 27, Lewis stated, “the country opens suddonly to extensive and beatifull plains and meadows which appeared to be surrounded in every direction with distant and lofty mountains.” The explorer was beholding the Spanish Peaks and Madison Range to the south, the Gallatin Range to the southeast and the Tobacco Root Mountains in his southwest view-field. He could also see the Bridger Range directly to the east and the wide lush Gallatin Valley. After naming the three forks of the Missouri – one for James Madison, a second for Albert Gallatin, the third for Thomas Jefferson – they followed the one they labeled “Jefferson’s river” in honor of the president.
Traveling against the current, the captains, desperate to find the Shoshone and trade for horses to get them over the mountains before winter, pushed themselves and their men to near exhaustion. Good news arrived on Aug. 8, 1805, when “the Indian woman (Sacajawea) recognized the ... hill she says her nation calls the beavers head – she assures us that we shall either find her people on this river or on the river immediately west of its source.” This historic limestone outcropping is now Beaverhead Rock State Park on the Beaverhead River, then “Jefferson’s river.”
Lewis, traveling on land and ahead of Clark, reached the end of “Jefferson’s River” and followed a well-worn Indian trail up Horse Prairie Creek to today’s Lemhi Pass. In doing so, on Aug. 12, 1805, he became the first known white man to have crossed Montana’s Continental Divide. Descending, he met the Shoshone and convinced them to follow him back to the confluence of the Red Rock River and Horse Prairie Creek to meet Clark and the rest of the party. Here on Aug. 17, they made their trading arrangements for the much-needed horses and called the place “Camp Fortunate.” Clark Canyon Reservoir has since drowned the site.
Leaving the watercraft behind, the explorers maneuvered their way over the treacherous Bitterroot Mountains and up the Bitterroot Valley. Following Lolo Creek, they fought snow and rugged terrain before exiting Montana.
After returning from the Pacific coast in July 1806, the Corps of Discovery divided into two groups at “Traveller’s rest” near Lolo, Montana. While Lewis headed to the “Great Falls of the Missouri” by way of the Blackfoot valley, Clark made his way down the Bitterroot Valley and crossed into the Big Hole Valley, which the Indians called “land of the big snows.” He christened the area “Hot Springs Valley” after discovering the now Jackson Hot Springs.
Crossing the present Big Hole Pass and overnighting in the vicinity of the headwaters of Divide Creek and its still flowing springs, Clark wrote “some butifull Springs – fall into Willards
(Grasshopper) Creek ... This extensive vally Surrouned with mountains (the Bitterroot Range and East and West Pioneers) – I now take my leave of this butifull vally which I call the hot spring Vally, and behold one less extensive and much more rugid on Willards Creek.”
Here Clark was referring to the land around Bannack and south to Horse Prairie Creek. On July 8, 1806, following an Indian road down Divide Creek, Clark turned south and tracked to Horse Prairie Creek where “we proceeded on down the forke – 9 Miles to our encampment of 17 Augt. (1805, Camp Fortunate) at which place we (had) Sunk our Canoes & buried Some articles.”
Words Lewis and Clark put to paper in July and August of 1805 and in July 1806, represent the first written record of southwest Montana. The tranquil landscape the Corps of Discovery left behind in the summer of 1806 would remain at peace for more than half a century.