Throughout the world, you’ll find that major areas of commerce are located near water. By far one of the most important rivers in the U.S. is the Mississippi River. Not only does it serve as the unofficial dividing line between the eastern and western halves of the country, but it has also played a pivotal role in the nation’s physical expansion.

Fast Facts About the Mississippi River

Credit: Nancy Bauer / Shutterstock

Before we dig into the river’s historical importance, here are some quick figures to give you an idea of the Mississippi River’s size and influence. The Mississippi River is 2,320 miles long and runs north to south, from Lake Itasca in Minnesota to the Gulf of Mexico in Louisiana. It is the nation’s second-longest river, surpassed only by the Missouri River which is 2,341 miles long.

A Natural Boundary

When the U.S. was formally recognized as a nation, it had only 13 states and was limited primarily to the East Coast with a few territories that spread westward. Over the years, the nation expanded to include newly ratified states and additional territories that were bounded by the eastern shores of the Mississippi River. It wasn’t until the Louisiana Purchase in 1803 when the U.S. expanded to cover significantly more land.

The Louisiana Purchase and a Ballooning Nation

Credit: Photo Image / Shutterstock

Even leading up to the Louisiana Purchase of 1803, America was already on an aggressive expansion path. More people continued to migrate to the country, and limited unclaimed agricultural land made it necessary for settlers to continue to look west. In the two decades between 1784 and the Louisiana Purchase, the nation had grown to sixteen states and four territories including the Indiana and Northwest territories in the Midwest and the Mississippi and extended Georgian territories in the South.

With the addition of the Louisiana Purchase, the young nation was able to double in size and gain control of one of the most influential rivers on the continent with a critical shipping and supply line. According to historians, this was a pivotal moment for America as it was one of the first major non-military international diplomatic overtures for the country. The Louisiana Purchase helped to push the U.S. onto the national stage and position the country as a critical political force to be recognized and respected. However, America wouldn’t be able to enjoy an uncontested claim over the Mississippi River until they successfully defeated the United Kingdom in the War of 1812.

Louis & Clark and Manifest Destiny

Credit: Art Wager / iStockPhoto

While the land east of the Mississippi had been surveyed, much of what lay west of the river was a mystery. President Thomas Jefferson commissioned Merriweather Lewis and William Clark to conduct an expedition to explore and survey the new lands. The 8,000-mile expedition took two years and spanned from the Mississippi River to the Pacific Ocean. It was considered a success because of the detailed geological and ecological surveys and reports that the duo created.

Louis and Clark’s travels paved the way for future expansion into what is now the American West. A massive population boom in the early 19th century caused by immigration made land hard to come by in the east. Coupled with two devastating depressions, immigrants and locals alike were looking for better opportunities and saw that moving west was their only means of doing so.

Many presidents embraced expansion, including James Monroe, Andrew Jackson, and John Tyler, who promoted a specific expansionist policy that eventually became Manifest Destiny. The concept led to the sometimes civil and often war-based annexation of the remaining contiguous portion of the country. This included the American Pacific Northwest, Wyoming, California, the southwest, and Texas. While the policy helped to expand the nation, it was done at the expense of international relations and featured well-documented abuses of indigenous people.

Today, the river remains incredibly important to the United States, though advances in transportation and technology have changed how it's used.