Thomas Jefferson and American Expansion

something that goes against the rules or laws written in the Constitution of a country

​​unconstitutional

​an increase in size

​​expansion

​By 1800, American citizens had different ideas about how the government should work. Many Americans thought the Alien and Sedition Acts put in place by John Adams were unconstitutional. Unconstitutional is something that goes against the rules or laws written in the constitution of a country.

Thomas Jefferson and the Democratic-Republicans opposed these acts. They thought the acts were unfair and that the government was using its power in the wrong way. They argued that the acts went against the First Amendment to the Constitution.

Thomas Jefferson defeated the former president, John Adams, in the presidential election of 1800.

Jefferson's strong point of view against the Alien and Sedition Acts helped him be elected as the third president of the United States in 1801.​

​Thomas Jefferson

In 1803, France took control of the land west of the Mississippi from Spain.

When this happened, Jefferson was worried about losing access to the Port of New Orleans, which was used for trading.

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The Louisiana Purchase

​The Louisiana Purchase was one of the largest land deals in history, and many consider it to be Thomas Jefferson's greatest achievement. The Louisiana Purchase helped the United States add more land, making it twice as big. This helped in the expansion of the United States.

Expansion means an increase in size. In this case, the land that the United States owned increased in size.

The Lewis and Clark Expedition

Soon after the Louisiana Purchase, Jefferson finalized plans for an expedition to explore the new lands. It was called the Lewis and Clark Expedition.

Meriwether Lewis was an American explorer.

He was also Thomas Jefferson's secretary.

Jefferson asked him to lead the expedition.

Meriwether Lewis

​William Clark was a friend of Lewis's.

They served in the army together.

Lewis asked Clark to go with him on the expedition.

William Clark

​Lewis and Clark formed the Corps of Discovery, a group of strong men who took a nearly two-year journey to the Pacific Ocean.

​​The Corps of Discovery

​Jefferson hoped the Corps of Discovery would find a water route that would link the Mississippi River with the Pacific Ocean. This route would provide entry to the Western part of North America.

Jefferson also wanted Lewis and Clark to learn about the Native Americans who lived in the West. In addition, he wanted them to bring back information about the type of land in the West.

​​Purposes of the Expedition

​See page 7 in Edio

You learned that Thomas Jefferson became the third president of the United States. He also was responsible for much of the expansion to the West.

You learned about the Louisiana Purchase and how that added to the land that belonged to the United States.

Finally, you learned about the Lewis and Clark Expedition, including the main goals of the expedition.

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Wrap Up