Cahokia
Overview
 
Cahokia Mounds State Historic Site (icon) is the area of an ancient indigenous city (c. 600–1400 CE) located in the American Bottom
American Bottom
The American Bottom is the flood plain of the Mississippi River in the Metro-East region of Southern Illinois, extending from Alton, Illinois, to the Kaskaskia River. It is also sometimes called "American Bottoms". The area is about , mostly protected from flooding by a levee and drainage canal...

 floodplain, between East Saint Louis and Collinsville
Collinsville, Illinois
Collinsville is a city located mainly in Madison County, and partially in St. Clair County, both in Illinois. As of the 2010 census, the city had a population of 26,016. Collinsville is approximately 12 miles from St. Louis, Missouri and is considered part of that city's Metro-East area...

 in south-western Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

, across the Mississippi River
Mississippi River
The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...

 from St. Louis, Missouri
St. Louis, Missouri
St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...

. The 2200 acres (8.9 km²) site included 120 human-built earthwork mounds
Earthworks (archaeology)
In archaeology, earthwork is a general term to describe artificial changes in land level. Earthworks are often known colloquially as 'lumps and bumps'. Earthworks can themselves be archaeological features or they can show features beneath the surface...

 over an area of six square miles, of which 80 remain. Cahokia Mounds is the largest archaeological site
Archaeological site
An archaeological site is a place in which evidence of past activity is preserved , and which has been, or may be, investigated using the discipline of archaeology and represents a part of the archaeological record.Beyond this, the definition and geographical extent of a 'site' can vary widely,...

 related to the Mississippian culture
Mississippian culture
The Mississippian culture was a mound-building Native American culture that flourished in what is now the Midwestern, Eastern, and Southeastern United States from approximately 800 CE to 1500 CE, varying regionally....

, which developed advanced societies in central and eastern North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, beginning more than five centuries before the arrival of Europeans.

Cahokia Mounds is a National Historic Landmark
National Historic Landmark
A National Historic Landmark is a building, site, structure, object, or district, that is officially recognized by the United States government for its historical significance...

 and designated site for state protection.
 
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