The United States of America grew as a nation from the thirteen original colonies hugging the Atlantic coastline into a transcontinental nation with ports on both the Atlantic and the Pacific oceans in just half a century. The young nation added millions of square miles of new territory by a variety of means, from simple purchases to outright military conquests. This paper will examine two events that led to large acquisitions of territory, two of the most important historical events in early American history. The first is the Louisiana Purchase of Thomas Jefferson, in which the Mississippi, Missouri, and Columbia river valleys were acquired from France. The second is the Treaty of Guadalupe Hidalgo, in which most of modern Southwestern United States, and all of California, were formally ceded after the military conquest of Mexico.
The Louisiana Purchase represents an area of over 500,000,000 acres. At the time of the purchase in 1803, the existing United States territory totaled only about 434,000,000 acres (Kukla, 2003, p. 287). Thomas Jefferson was president at the time of the purchase, and had had his eye on the Louisiana territory at the least since he had served as ambassador to Paris in 1786 (p. 20). Like many men of his era, Jefferson was something of a jack-of-all-trades. He was a lawyer and a politician yes, but he was also a farmer, a businessman, and a scientist. One of the many interests of Jefferson was geography, especially the geography of the land he had helped to birth (p. 3). For years, he had been collecting information about the interior of the North American continent beyond the borders of the 13 colonies. Jefferson knew that the Mississippi river and its major tributaries serviced the continent like arteries service a human body, and that the boon to commerce that this river system presented was essential to the future of the nation (Kennedy, 2003, p. 114). He knew, too, that his young nation was...