What Is the Lewis and Clark Expedition?

Alex Tree

The Lewis and Clark expedition was one of the first large-scale explorations of the Pacific Northwest in the United States of America. This expedition was led by Meriwether Lewis and William Clark, two former soldiers chosen by then President Thomas Jefferson. The cross-country expedition had several goals, including judging the resources acquired in the Louisiana Purchase, declaring sovereignty over the Indian tribes in the area, and discovering a direct water passage across the country for easy trade. On the way, the group met many Native Americans, hired interpreters to communicate and trade with the Indians, and documented the appearance of animals they had never seen before.

A statue of Thomas Jefferson inside the Jefferson Memorial. Jefferson sent Lewis and Clark to explore the Pacific Northwest.
A statue of Thomas Jefferson inside the Jefferson Memorial. Jefferson sent Lewis and Clark to explore the Pacific Northwest.

Thomas Jefferson wished to make the first claim to discovery of the Pacific Northwest, before the British or anyone else. He ordered Meriwether Lewis, the official leader of the Lewis and Clark expedition, to follow the rivers, map the course, and collect scientific data. While the expedition was the first official U.S. exploration of the northwestern coast, Europeans and Canadians had been there before, the latter who wrote a book that influenced the president to start his own expedition.

Lewis and Clark led the first expedition to the Pacific Coast of America.
Lewis and Clark led the first expedition to the Pacific Coast of America.

The Lewis and Clark expedition started with fewer than three dozen people at what is now known as Hartford, Illinois. It was spring of 1804 when the group set out and followed the Missouri River to reach the first settlement on the journey. The expedition nearly battled with tribes on several occasions, especially when they needed to pass through inhabited territory or when animals or weapons went missing. Without the indigenous people of America, however, the Lewis and Clark expedition would have failed due to starvation or losing their way in the Rocky Mountains. For the most part, Lewis and Clark tried to keep trade negotiations peaceful and provide demonstrations of technology and gifts of alcohol when they could.

The Lewis and Clark expedition started near St. Louis, Missouri.
The Lewis and Clark expedition started near St. Louis, Missouri.

When the Lewis and Clark expedition came to an end in 1806, the result was the very first accurate maps of the area and a better understanding of plants and animals previously unknown to the American, though not indigenous, people. More than 140 maps, 200 plants and animals, and 70 Native American tribes were created, described, and noted, respectively.

The Louisiana Purchase allowed Americans to use the Mississippi River and the Port of New Orleans for trading.
The Louisiana Purchase allowed Americans to use the Mississippi River and the Port of New Orleans for trading.

Due to the major contributions to scientific research and the impact the expedition had on increasing the United States’ lands, there are numerous buildings, structures, and animals named after Lewis and Clark. In addition, their grave sites are still maintained and occasionally a place of celebration. During these celebrations, plants the men discovered are placed on their graves.

The Louisiana Purchase Treaty was signed April 30, 1803, transferring claim to the property from France to the United States.
The Louisiana Purchase Treaty was signed April 30, 1803, transferring claim to the property from France to the United States.

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Discussion Comments


When my kids were learning about this in school they played an interactive game that was a Lewis and Clark Expedition for kids.

I found that I really enjoyed playing this game with them. I think this is a great way for them to get more of a realistic view of what happened.

When I play the game with them, I learn so many things that I never knew, or forgot from many years ago. This is a great way for them to learn and remember, and much more interesting than only reading it in a book.


I enjoy nature and spending as much time outdoors as possible. What I find fascinating about this expedition is how exciting it must have been to document the plants and animals they encountered along the way.

Surely this would have been much more exciting than watching this on TV like we do today. Even when I go to the zoo, I find it easy to just sit and watch different animals I haven't seen before.

I can imagine how exciting this must have been to see them in their natural environment.

There are a lot of different types of plant and flowers in my state alone. I would be curious to know many pieces of paper or books were used for the purpose of documenting plants they encountered along the way.

Then the information they received from the Indian tribes on ways to use these plants for medicinal purposes was probably invaluable to them.


@andee - It is very interesting to read about the communication between the Native Americans and Lewis and Clark.

Being on good terms with the Indians was crucial to their journey. I remember reading that one of the things they tried to get the Indians to do was stop fighting with each other.

It was hard for the Indians to understand this. They thought if there was peace between the tribes, they wouldn't need their chiefs.

I don't know how long it would take if you followed a map of the Lewis and Clark expedition route today. We think nothing of getting in our cars and driving from state to state.

They didn't have the luxuries we have today and were faced with bad weather and health challenges along the way.


I find it amazing that these two men actually were able to stay alive during this entire expedition.

I remember reading about this in school, but I watched a Ken Burns show on PBS about the Lewis and Clark Expedition and really learned a lot.

There are many things that are much more interesting when you are an adult than when you have to learn something for school.

It must have been somewhat unsettling meeting all the Indian tribes and not knowing how they were going to react to them. Presenting gifts is always a good place to start!


This was the kind of expedition that makes me glad that there are brave people out there willing to sacrifice for the good of the nation. The article says they were former soldiers, but I view what they did for the country as an act of service in the face of danger, so I consider them soldiers during the expedition, as well.

They knew very well going into it that the chances of death were high. They also knew that they were going through with it to enhance the future of their people and land. It took a true spirit of bravery and courage to endure the two years worth of peril.


I'm glad that Lewis and Clark discovered so many plants along their way. Without their expedition, it would have taken many years for settlers to discover these plants and their uses on their own.

I know that they had lots of help from the Native Americans with this. They observed how they were already making use of certain plants, and they learned from them.

I have read that they discovered blue flax, which the Native Americans used to make nets for fishing and ropes. They even discovered wild licorice, and even back then, the natives were eating it like candy.

They also discovered one of my favorites, Indian blanket. The flowers are orange, red, and yellow, and even back then, the natives said the plant represented sunshine and happiness.


@orangey03 – You bring up a good point about the expedition being over. What an exciting rush it must have been to explore unknown territory! To do this for two years would have meant getting used to having the thrill on a daily basis.

I have read that he was still working on his expedition journals when he died. Maybe he was depressed that all he could do then was write about it, rather than go out and live it some more.

However, you would think that he would want all of that hard work to be accurately recorded. It seems unlikely that he would kill himself without first finishing an account of those explorations. Because of this, I lean more toward the homicide theory of his death.


I have been to the Meriwether Lewis grave site on the Natchez Trace Parkway, and the area around it has trails, bathrooms, and an information center. There is even a gift shop there that has books about the history of the Trace and Lewis himself.

I learned there that it is believed he died of a self-inflicted gunshot. However, there are people that doubt this. Some stories have held that he was shot in the back, so he couldn't have done it himself.

Some of his friends said that he was very depressed because the expedition was over, and he was stuck working at a desk. Some say he had wild mood swings and strange behavior in general, but we will never know the real story. I say that if he really was shot in the back, there is no way he could have done it, no matter how depressed he may have been.


I was surprised that this article doesn't mention Sacagawea by name! Her role may have been overstated, sure, because it makes such a good story, but she's the third name that everyone recognizes from this expedition. She didn't exactly guide them, but she helped them as an interpreter, etc. And there's nothing like a woman carrying a baby (yep, she did the whole thing with her baby strapped to her back) to make a group look less threatening to strangers.

Some friends of mine in college were *huge* Lewis and Clark buffs. They actually retraced the route of the expedition - but it only took them most of one summer, as they were traveling by Ford Mustang rather than walking! My friend told me that the Lewis and Clark expedition journals refer to Sacagawea mostly as "the squaw." Some people see that as diminishing her role, but he seemed to think that they just couldn't spell her name!


One of the interesting Lewis and Clark expedition facts is that they hardly lost anybody on the trip. They lost only one man! It's incredibly when you think about them traveling for two years, through more than one winter, in unfamiliar territory with wild animals, indigenous peoples whose ways and languages they did not know, with no modern equipment.

It's interesting, too, that they went all the way to the Pacific - which is much further than the land of the Louisiana Purchase. Early sense of Manifest Destiny, maybe?

You can learn a lot about the expedition in St. Louis, where they have the Gateway Arch to mark the jumping-off point. The Arch really is worth going up - it's one of those few architectural wonders that really does not disappoint.

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