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Louisiana Purchase (1803)
The Louisiana Purchase, the greatest achievement of the presidency of Thomas Jefferson, more than doubled the territory of the United States by adding the entire Mississippi Valley west of the river itself. The United States purchased the land from Napoleon Bonaparte, first consul (and later emperor) of France, on April 30, 1803. The land was purchased for about $15 million, through a treaty of cession.
The United States needed New Orleans to secure free passage on the Mississippi River. Spain, the previous owner of Louisiana, had blocked Americans from traveling on the river. The poor state of roads in this era meant that farmers and merchants who did not have access to riverways could not effectively trade or acquire needed supplies. The 1784 closure of the ...