Cahokia Mounds State Historic Site

Location: Collinsville, Illinois

Webpage: Illinois State Park

General Description: The Cahokia Mounds State Historic Site is the site of a Pre-Columbian Native American city dating from 1050-1350 CE.  Although there is evidence of occupation during the Late Archaic Period (around 1200 BCE, Cahokia as it is now defined was first occupied around 600 CE during the Late Woodland Period.  About the 9th Century CE, the emergent Mississippian Culture began the construction of temple mounds at this site.  Cahokia became the cultural center for the Mississippians with settlements  across the midwest, east, and southeastern US.  Due to its strategic location near the confluence of the Mississippi, Missouri, and Illinois River, it maintained trade links with the Great Lakes to the north and the Gulf Coast to the south.  The city began to grow quickly from its beginnings of around 1000 inhabitants in 1050 to 10,000-15,000 by 1100.  Including the surrounding farming areas the numbers are likely to have been more than 40,000, which is larger than any American cities until 1780 and larger than 13th century London.  The population density began to decline in the 13th century and eventually abandoned by 1300.  While due to a large number of factors, these certainly included overhunting, deforestation, flooding and potentially warfare, although there is no direct evidence of this.  The original site covered 120 mounds over 6 square miles, of which, 80 remain today.  The largest, Monks Mound, covers 14 acres, rises 100 feet, and was topped by a massive 5,000 square foot building rising another 50 feet.  Monks Mound was the center of four large plazas in each cardinal direction, each of which were leveled by the inhabitants.  The high status central area of Cahokia was surrounded by a 2 mile long wooden palisade with protective bastions, which was rebuilt at least four times.



1) Unfortunately, we visited on a Tuesday when the Visitor Center was closed, so we did not get the opportunity to view the exhibits.  However, this also meant that we had the grounds largely to ourselves.  The entire historic site covers 2200 acres with the remains of mounds scattered throughout the area.  There are numerous trails of varying lengths from less than a mile to multiple miles.


2) There is a short trail that circles the Twin Mounds from the Visitor Center.  These mounds are within the central palisade and are likely the site of burials with the east mound is flat on top and likely had a structure used to prepare the dead for burial in the west mound.  Since most of the dead were buried in cemeteries, these burial mounds were likely used just for the leaders of the community.

3) The most imposing structure is Monk’s Mound which is the largest earthen construction in the Americas, containing 22 million cubic feet of earth all of which had to hauled by hand in woven baskets.  The base covers 14 acres and rises 100 feet in three levels.  The mound is named for the French Trappist monks who lived on a nearby mound from 1809-1813 and used the large terraces for farming.  There is a stairway up the south side of the mound leading to each of the three terraces.

4) To the east of Monks Mound are the uncovered evidence of Woodhenge, which are four overlapping circles of wooden posts used to track the seasons.  The circles are of different sizes and were built at different times.  Today they have reposition posts around the largest of the three circles and painted the posts that would line up the summer and winter solstices.