Significance of Louisiana Purchase

February 2, 2023
US Postage Commemorating the

US Postage Commemorating the 50th Anniversary of the Louisiana Purchase

US Postage Commemorating the 50th Anniversary of the Louisiana Purchase

Focus Question: What was the importance of the Louisiana Purchase?

For more information on the Louisiana Purchase and Thomas Jefferson's Presidency, see United States History USI.22

The Louisiana Purchase Treaty


For a long time, France refused to give up control of its territories on the North American continent. In the early 1800s, however, Napoleon was on the verge of a war with Great Britain and was in dire need of money.

President Thomas Jefferson took advantage of this situation and offered to buy New Orleans from France. Napoleon offered to sell the entire Louisiana Territory for $15 million, which averaged out to around 4¢ an acre.

Jefferson agreed and purchased 830, 000 square mile of land west of the Mississippi, which doubled the country’s size and opened up the possibilities for westward expansion.

The Louisiana Purchase TreatyThose who opposed the acquisition of the Louisiana Territory questioned its constitutionality. Jefferson was known for his strict interpretation of the Constitution, and this attempt at acquiring territory called into question the legitimacy of his political philosophy. The purchase also lead to an increase in sectional tension, both North/South and East/West.

Map of the US, Louisiana Purchase

The Importance of Louisiana for the United States

Many white Americans had moved as far west as the Mississippi River by the time of the Louisiana Purchase.
  • The river was a great resource for them. Many traveled down the river all the way to Louisiana, where it emptied out into the sea in New Orleans. This was an extremely important location from them because it was a port used for international trade. Now that the United States owned this important location, they could have the freedom to use it as they wished. Because it was so important for trade, it was also important for the economy.

  • The Louisiana Purchase was also significant because it doubled the size of the United States. At the time, expansion was important because the United States wanted to become as big and powerful as possible. Up until then, very few whites had been west of the Mississippi River.
  • Gaining Louisiana opened up the West to them—in the years to come they would continue to expand westward.Map of the US, Louisiana Purchase But this westward expansion had horrible effects on many native peoples who were forced to leave their lands once white Americans began to take them over.

Map of New Orleans, 1816, as reprinted in 1880s with more recent developments contrasted.

Political details of the Louisiana Purchase

France had at one time controlled the New Orleans port, but around 1800 it was owned by Spain. The United States was not threatened by Spain, but when President Thomas Jefferson heard that the territory might be transferred back to France he got worried. In fact, the whole nation was worried. It was probably the biggest thing in the news at the time.

Jefferson thought they might have to fight to get any of the benefits of the Mississippi River and the New Orleans port. So he prepared for war. At the same time, he sent James Madison to France to negotiate a plan. By the time Madison got the France, however, he found out that the French were already planning on selling the territory to the U.S. A treaty was drafted and the sale was made, for 15 million dollars.

Primary Source:



Norton, et al, Mary Beth (1994). A People and a Nation. Boston: Houghton Mifflin Company.
Wilson, Gaye (March, 2003). Jefferson's West. Retrieved April 12, 2007, from Monticello, the Home of Thomas Jefferson Web site:
(2003). The Louisiana Purchase Exhibit. Retrieved April 12, 2007, from The Louisiana Secretary of State Web site:
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