Humanities › Geography The Louisiana Purchase and the Lewis and Clark Expedition Share Flipboard Email Print The 2005 U.S. nickel, issued for the 100th anniversary of the Lewis and Clark Expedition to the Louisiana Purchase. Getty Images Geography Key Figures & Milestones Basics Physical Geography Political Geography Population Country Information Maps Urban Geography By Colin Stief is an experienced project manager for environmental organizations. He holds a master's degree in environmental management from Duke University. our editorial process Colin Stief Updated August 15, 2018 On April 30, 1803 the nation of France sold 828,000 square miles (2,144,510 square km) of land west of the Mississippi River to the young United States of America in a treaty commonly known as the Louisiana Purchase. President Thomas Jefferson, in one of his greatest achievements, more than doubled the size of the United States at a time when the young nation's population growth was beginning to quicken. The Louisiana Purchase was an incredible deal for the United States, the final cost totaling less than five cents per acre at $15 million (about $283 million in today's dollars). France's land was mainly unexplored wilderness, and so the fertile soils and other valuable natural resources we know are present today might not have been factored in the relatively low cost at the time. The Louisiana Purchase stretched from the Mississippi River to the beginning of the Rocky Mountains. Official boundaries were not determined, except that the eastern border ran from the source of the Mississippi River north to the 31 degrees north. Present states that were included in part or whole of the Louisiana Purchase were: Arkansas, Colorado, Iowa, Kansas, Minnesota, Missouri, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming. French explorer Robert Cavelier de la Salle claimed the Louisiana Territory for France on April 9, 1682. Historical Context of the Louisiana Purchase France controlled the vast stretches of land west of the Mississippi, known as Louisiana, from 1699 until 1762, the year it gave the land to its Spanish ally. The great French general Napoleon Bonaparte took back the land in 1800 and had every intention of asserting his presence in the region. Unfortunately for him, there were several reasons why selling the land was all but necessary: A prominent French commander recently lost a fierce battle in Saint-Domingue (present-day Haiti) that took up much needed resources and cut off the connection to the ports of North America’s southern coast.French officials in the United States reported to Napoleon on the country's quickly increasing population. This highlighted the difficulty France might have in holding back the western frontier of American pioneers.France did not have a strong enough navy to maintain control of lands so far away from home, separated by the Atlantic ocean.Napoleon wanted to consolidate his resources so that he could focus on conquering England. Believing he lacked the troops and materials to wage an effective war, the French general wished to sell France's land to raise funds. The Lewis and Clark Expedition to the Louisiana Purchase Traveling 8,000 miles (12,800 km), the expedition gathered huge amounts of information about the landscapes, flora (plants), fauna (animals), resources, and people (mostly Native Americans) it encountered across the vast territory of the Louisiana Purchase. The team first traveled northwest up the Missouri River, and traveled west from its end, all the way to the Pacific Ocean. Bison, grizzly bears, prairie dogs, bighorn sheep, and antelope were just a few of the animals that Lewis and Clark encountered. The pair even had a couple of birds named after them: Clark’s nutcracker and Lewis’s woodpecker. In total, the journals of the Lewis and Clark Expedition described 180 plants and 125 animals that were unknown to scientists at the time. The expedition also led to the acquisition of the Oregon Territory, making the west further accessible to the pioneers coming from the east. Perhaps the biggest benefit to the trip, though, was that the United States government finally had a grasp on what exactly it had purchased. The Louisiana Purchase offered America what the Native Americans had known about for years: a variety of natural formations (waterfalls, mountains, plains, wetlands, among many others) covered by a wide array of wildlife and natural resources.