Mounds of Civilization: Cahokia
The term "mound builder" collectively refers to an indigenous people who used earthen mounds for a various assortment of purposes. In some instances, mounds were used as mass graves, or single graves for important or divine individuals. In other instances, they were used for ceremonial purposes. The mounds, in many ways, are akin to the pyramid designs in Egypt and the stepped pyramids of Mesoamerica. The largest concertation of mound builders was centered on the Mississippi River Valley and the tributary rivers. The most famous example of these mounds is in Cahokia, where the mound structures there indicate an immense civilization once dwelled there.
Mississippian culture is defined as a nation, or nations, that were centered exclusively on the Mississippi ranging from just north of Prairie Du Chien south to approximately Cape Girardeau. It may have extended as far west as the Red Hills, and as far east as the eastern end of Lake Erie. There are some discrepancies depending on the sources you reference. This nation would have existed from approximately 900 AD to around 1400 AD. For a comparison, the reign of the pharaohs in ancient Egypt ran from about 3100 BC to around 100 BC, and the Olmec's lived in Mesoamerica between 1200 and 400 BC. There is an exception to this however, and it is this exception that is the most curious and has fascinated scholars for quite some time: Cahokia.
The settlement of Cahokia peaked sometime between 1200 and 1300 AD. Some estimations put this relic city's population upwards of 50,000, making it the largest northern settlement up to that point in the Americas. The ancient city of Teotihuacan predated Cahokia as the largest settlement in 450 CE with a population of almost a quarter million. Cahokia had no fewer than ten mounds clustered around what was believed to be a city center. Outward from this center extended numbers of smaller huts and mud structures. Archeological surveys conducted at this site continue to expand the city outward, and population estimates continue to increase. The upper limit of the population suggested approaches 100,000 - which would make it the largest mound city to be built.
There is still some mystery surrounding the abandonment of Cahokia. However, the most likely reason can be found further south in the westernized settlement of Kaskaskia. Here, Americans had settled what was once the state capitol of Illinois territory. When the capital was moved in the 1820s, much of the population moved to the state center. However, Kaskaskia remained an incorporated town for a while after that. It was not until floods struck Kaskaskia that the population dwindled. It is theorized that the volatile nature of floods on the Mississippi is especially voracious in this part of the river. The river may have flooded the town or caused long-term damage to hunting grounds or vegetation in the area. Repetitive floods may have also caused the issue, such as what happened in Kaskaskia.
Elsewhere on the Mississippi, some mounds have been carbon dated to as early as 4500 BC. These mounds, predating the Mississippian, were found in Louisiana - officially putting humans as far south and east into the Americas as Baton Rouge. Falling squarely in the Archaic period, these mounds represent the earliest known settlements in the United States, and some of the oldest settlements in North America - predated only by the Lithic era.
Many different types of mounds served many different purposes, as previously stated. One of the most fascinating types of mounds are the ones that take the form of spiraling serpents. The most famous of these is the Serpent Mound in Ohio, but many others - such as the one in Dubuque - exist on a far smaller scale. The exact purpose of these mounds is unknown.
Thousands of these structures can be found along and east of the Mississippi River and throughout the eastern seaboard. West of the river - especially beyond Missouri - soil composition was not conducive for such features. However, there are many examples of unique design, architecture, and art in ancient findings in the Rocky Mountains and points west as well.
Cahokia remains the best kept and intact example of the mound builders. Today, a state sanctioned museum operates depicting the history of the mound builders and the old city of Cahokia proper. Monks Mound also remains relatively intact and is a UNESCO National Historic Site.
