In Chapter 7, we learn about the story behind the Louisiana Purchase. We all learned about this historic land-grab, but there were some parts of this chapter where Wulf discussed aspects about the purchase which I had never heard about. Immediately following the slave revolt in Haiti, France was in need of some serious cash. Knowing this, and wanting as few Europeans involved in North America as possible, Jefferson brokered a deal to buy 800,000 square miles of open territory for a measly $15 million. However, this purchase might not have been possible if it weren't for some serious luck for the United States. Because the force of 25,000 men that was intended for New Orleans either died in battle or due to the malaria epidemic. This was quite literally the straw that broke the camel's back. Napoleon understood that we could no longer support expansion and expeditions in North America, so he essentially gave the Louisiana territory to the United States.

After Jefferson and the United States had purchased this vast and mostly unexplored territory, it was time to map what exactly our third President had bought. This was the job of Meriwether Lewis. After the purchase, Jefferson grew even more excited, saying the purchase "increased infinitely the interest we felt in the expedition". Jefferon had two main goals for this journey of epic proportions. First, he wanted Lewis to scout what the land held. Few Europeans had ever set foot west of the Mississippi River, let alone explored from the Missouri River all the way to the Pacific Ocean. This was the boldest undertaking for a young nation which was less than two decades old. Jefferson's second motive for the purchase was to push the United States westward. The former colonies, now states, were about to discover the phenomena of Manifest Destiny. After the victory over the British in the War for Independence, and the expulsion of the French and most of the Spanish, there was really no major force stopping the early states from expanding and forming one of the most geographically diverse nations in all the world. Finally, Jefferson the gardener was curious as to what lay ahead in this unexplored land. Wulf writes about Jefferson, "Maybe Lewis would find the huge mastodon roaming across the plains, discover profitable crops, flowers in exotic shapes and sizes, and trees that would soar even higher than those already encountered". Jefferson is excited about this purchase because of the opportunity if gives this young nation to expand, but also for the treasures nature might give in these unexplored lands. Jefferson hopes that this nation will thrive off the horticultural diversity.

As Jefferson stated at the beginning of Chapter 7, he believed this purchase to be "the most important and beneficial transaction...since the Declaration of Independence". The editor for the National Intelligencer wrote that this purchase made Jefferson "immortal" because this new territory included New Orleans, Louisiana, the Mississippi River valley, and the whole Midwest. All for $15 million. A mere 3 cents an acre.