When you think about where Lewis and Clark went, the mind usually jumps to a blurry image of two guys in buckskins pointing at a mountain. We're taught the broad strokes in middle school: they left St. Louis, found some western territory, and hit the Pacific. But if you actually trace their footsteps across the 8,000-mile round trip, the reality is way more chaotic, dangerous, and specific than the "scenic hike" version we often imagine.
Honestly, they didn't just "go West." They navigated a labyrinth of rivers that tried to sink them, crossed mountains that almost starved them to death, and survived a accidental shooting by one of their own men.
The journey technically started way before the famous 1804 departure. Most people miss the fact that Meriwether Lewis spent the summer of 1803 in Pittsburgh, Pennsylvania. He was overseeing the construction of a 55-foot keelboat. This wasn't just a casual boat; it was the "command module" of their fleet. He then floated down the Ohio River to meet William Clark in Clarksville, Indiana. From there, they set up shop at Camp Dubois in Illinois, right across from the mouth of the Missouri River. This was their "shakedown" camp where they spent the winter of 1803-1804 getting the men into shape.
The Grind Up the Missouri
On May 14, 1804, the Corps of Discovery officially pushed off into the Missouri River. They weren't moving fast. Imagine trying to row, pole, or literally tow a 12-ton boat upstream against a massive current.
They were basically doing 7 to 10 miles a day. It was grueling work. They passed through what is now Kansas City and Omaha, reaching the high plains of South Dakota by late summer. One guy, Sergeant Charles Floyd, didn't make it. He died near present-day Sioux City, Iowa, likely from a ruptured appendix. He's the only member of the expedition to die during the entire two-year journey, which is kind of a miracle given what came next.
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By October, they hit North Dakota. They realized they weren't going to make the coast before the snow flew, so they built Fort Mandan near the Knife River. This is where they met a French-Canadian trapper named Toussaint Charbonneau and his teenage Shoshone wife, Sacagawea.
Where did Lewis and Clark go after the winter?
In April 1805, the "permanent party" headed further into the unknown. They reached the confluence of the Missouri and Yellowstone rivers (near the North Dakota-Montana border) and kept pushing west.
Montana was where things got weird. At the Great Falls of the Missouri, they expected a single waterfall. Instead, they found five massive cascades. It took them an entire month to "portage" their gear—meaning they had to drag heavy canoes over 18 miles of rough terrain, prickly pear cactus, and grizzly bear territory. It was a nightmare.
The Continental Divide
By August 1805, Lewis reached Lemhi Pass on the border of Montana and Idaho. He expected to reach the top, look down, and see a gentle river leading straight to the Pacific.
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He was wrong.
He saw more mountains. Range after range of the Rockies stretched out like a stone wall.
This was the moment of truth. They needed horses to cross those mountains before winter hit. In one of those "too strange for fiction" moments, the Shoshone tribe they encountered was led by Chief Cameahwait—who turned out to be Sacagawea’s long-lost brother. That coincidence basically saved the expedition. They got the horses they needed and began the trek over the Bitterroot Mountains.
Starvation and the Home Stretch
The crossing of the Lolo Trail in Idaho was the low point. They ran out of food. They had to eat some of their horses to survive. They were frostbitten and exhausted by the time they stumbled onto the Weippe Prairie, where the Nez Perce people took them in and fed them.
From there, it was (literally) all downhill. They built new canoes and hit the water:
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- The Clearwater River
- The Snake River
- The mighty Columbia River
On November 7, 1805, Clark famously wrote "Ocian in view! O! the joy." He was actually looking at the massive estuary of the Columbia, still about 20 miles from the sea, but the salt spray was in the air. They spent the winter of 1805-1806 at Fort Clatsop, near Astoria, Oregon. It rained almost every single day. They were miserable, their clothes were rotting off their backs, and they were ready to go home.
The Split on the Way Back
When they headed east in 1806, they didn't just follow the same path. Once they got back to the Montana area, the group split up to explore even more territory.
- Lewis took a northern route to explore the Marias River. This is where he had a violent encounter with the Blackfeet nation, leading to the death of two Blackfeet men—the only fatal conflict of the trip.
- Clark headed south to explore the Yellowstone River. On July 25, 1806, he carved his name into a rock formation he called Pompeys Pillar (named after Sacagawea's son). You can still see his signature there today.
They reunited near the mouth of the Yellowstone in August. The trip back down the Missouri was a blur of speed because they were moving with the current now. They were hitting 50 miles a day. On September 23, 1806, they pulled back into St. Louis. People were shocked; most had assumed they were long dead.
Practical Ways to See the Route Today
If you want to see where Lewis and Clark went without the threat of grizzly bears or scurvy, the Lewis and Clark National Historic Trail covers nearly 4,900 miles.
- Great Falls, Montana: Visit the Interpretive Center to see just how brutal that 18-mile portage really was.
- Astoria, Oregon: You can walk through a replica of Fort Clatsop and feel the dampness of the Pacific Northwest air they complained about so much.
- Pompeys Pillar, Montana: This is the only place on the entire trail where you can see physical evidence of the explorers (Clark’s signature) still in its original location.
You've got thousands of miles of highway following the general path, but the best way to understand the trip is to get near the water. The Missouri River still has sections—like the White Cliffs in Montana—that look exactly as they did in 1805. Basically, if you want to know where they went, you have to look for the places where the mountains still look impassable and the rivers still run fast.
To dig deeper into the actual geography of the journey, you can access the original journals digitized by the American Philosophical Society or visit the National Park Service's interactive trail map. Looking at the topography of the Lemhi Pass is usually the "aha" moment for most people—it’s where you realize just how impossible their mission actually felt in the moment.