Mississippian Culture and Aztalan | Wisconsin Historical Society

Historical Essay

Mississippi Culture and Aztalan

The Genesis of Modern Wisconsin

Mississippian Culture and Aztalan | Wisconsin Historical Society
EnlargeMap mounted on cloth with lot and block numbers

Trempealeau, 1854

This map is mounted on cloth and shows lot and block numbers, streets, additions, and public squares. Also included is information on Trempealeau, an inset map that shows major cities and lakes around Trempealeau, and a list of "names of original proprietors of the village plat." View the original source document: WHI 112442

Around 1000 C.E., emigrants from Cahokia, across the Mississippi River from modern St. Louis, settled in northern Illinois. Archaeologists call their culture "Middle Mississippian." Shortly after migrating to northern Illinois, the Middle Mississippians moved up the Mississippi and Rock River valleys into Wisconsin.


At its peak, between 1100 and 1200 C.E., Cahokia was a massive community with a population of between ten and forty thousand (larger than London, Paris, or Rome at the time). The city centered on a vast open plaza surrounded by tall platform mounds, and circled by a massive palisade. Additional plazas, platform mounds, burial mounds, cemeteries, residential neighborhoods, workshops and cornfields extended for miles in all directions.

Cahokia gave rise to a number of small communities across the upper Midwest. Residents engaged in corn agriculture, pottery production and trade with their Woodland neighbors. The Middle Mississippians soon created a vast trade network that moved valuable items across the continent and exposed Woodland peoples to Middle Mississippian culture.

Trempealeau and Aztalan

EnlargePhotographic postcard of one of the Indian mounds at Aztalan State Park.

Ancient Aztalan

Photographic postcard of one of the Indian mounds at Aztalan State Park. Steps lead up to the top of the mound from the right, and a tall fence is behind it on the left. Aztalan, Jefferson County, Wisconsin. View the original source document: WHI 101833

Some northern Mississippian outposts were in Wisconsin. The largest were located at the modern city of Trempealeau and Aztalan on the Crawfish River  now a Wisconsin state park. The residents of Trempealeau built a ceremonial complex of platform mounds overlooking the valley below. Because excavations have been limited, archaeologists know little about this mysterious community.

Woodland peoples  descendants of the local Effigy Mound culture  had already settled the site of Aztalan by 1100. They were joined by Middle Mississippian immigrants, who transformed the village into a miniature version of Cahokia. The remodeled town boasted a central plaza, platform mounds topped with temples and an elaborate fortification wall.

At both Aztalan and Trempealeau, archaeologists have found pottery that was made in Cahokia and then carried north. Evidence of cultural interaction between Woodland peoples and their Mississippian neighbors has been found at sites across Wisconsin. Relations may not always have been peaceful, however. Excavations at many Middle Mississippian sites have uncovered evidence of warfare such as Woodland and Middle Mississippian communities surrounded by defensive stockades.

Rise of Oneota

By approximately 1200, Aztalan and Trempealeau were abandoned. Near the same time, Cahokia slipped into decline. These cultures evolved into the new Mississippian culture known as Oneota. The new civilization began to expand across the Midwest, giving rise to many of the tribal groups known today.

You can visit Aztalan today, stand inside their re-created stockade and climb their pyramids. The first European description of Aztalan was written by Nathaniel Hyer in 1837. Mistakenly thinking the platform mounds must have been related to Aztec pyramids in Mexico, Hyer gave the site its popular name. The first scientific examination of Aztalan was made by Milwaukee scientist Increase Allen Lapham in the summer of 1850. Since then, many archaeologists have visited and worked at the site, shedding light on a pivotal moment in Wisconsin's history.

Learn More

[Sources: Birmingham, Robert A. and Leslie E. Eisenberg. Indian Mounds of Wisconsin (Madison, Wis.: University of Wisconsin Press, c2000). Theler, James L. and and Robert F. Boszhardt. Twelve Millennia: Archaeology of the Upper Mississippi River Valley (Iowa City : University of Iowa Press, c2003). The History of Wisconsin: volume 1, From Exploration to Statehood by Alice E. Smith. (Madison, State Historical Society of Wisconsin, 1973)]