Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

A depiction of Mississippians at the site of Aztalan State Park. © Friends of Aztalan State Park. Montage design by Marifrances A. Cataldi

A depiction of Mississippians at the site of Aztalan State Park.
© Friends of Aztalan State Park. Montage design by Marifrances A. Cataldi

October 2009

Who were they and why did they leave?

We've only scratched the surface in unearthing the remains of an ancient people and one of our great cultural mysteries at Aztalan State Park.

Natasha Kassulke

A Guide at Your Side

As temperatures climb into the mid-80s, about 35 people are standing alongside the Crawfish River in the shade of an immense stockade wall. In the distance, children race up the steps of a large terraced, flat-topped mound. Couples hold hands, don sunscreen and carry digital cameras.

About a thousand years ago on this same day – the summer solstice – the plaza below the mound might have been bustling with a different event. Perhaps a heated game of "chunkey" would have been waged. Certainly the Native American Indian city of about 500 would have been abuzz preparing food for the impending solstice celebration marking the first day of summer and longest day of the year.

Today, though, quiet picnics unfold on freshly mowed grass instead of the great annual Green Corn Ceremony of the past.

Aztalan State Park is Wisconsin's premier archaeological site. It's a national landmark and listed on the National Register of Historic Places. It's a prehistoric marvel and a mystery.

The Wisconsin Department of Natural Resources is the largest guardian of state archaeological properties, and DNR archaeologist Mark Dudzik calls Aztalan "the crown jewel" of the state's collection. Located in a glacial drift region in Jefferson County, Aztalan is a cultural landscape that has hinted at, but not yet given up many of its secrets.

Cultural landscapes are the worlds we create around our homes and include a mix of natural features such as hills and rivers, and monuments such as cemeteries or ball parks. These features define what we think is important about our surroundings and how and why we use them.

During a tour of the site organized by the Natural Resources Foundation, Dudzik and former Wisconsin State Archaeologist Bob Birmingham who also directs the Aztalan Friends group, explain that the Indian occupants who built these stockade walls have been traced to a mother site at Cahokia, a large Middle Mississippian settlement in west-central Illinois located near present day St. Louis, Missouri. Cahokia housed 20,000 people and covered five square miles. At the north end of Cahokia's "urban" center is the 14-acre Monks Mound, the largest prehistoric earthen construction in North America.

"You are at the northern outpost of a great civilization and very complex society," Birmingham tells the Aztalan tour group. "I think that the Mississippian civilization is comparable to the great civilizations around the world."

The people who settled Aztalan built large, flat-topped pyramidal mounds and a stockade around their village. Decades of archaeological research, including carbon dating and tooth samples found at the site that were traced back to Cahokia, have provided some clues to the culture that created these mounds. It was once a village and ceremonial complex of about 500 people that thrived between 1000 and 1300 AD before the site was mysteriously abandoned.

This reconstructed mound at Aztalan may have been the home site of a chief. © Kristen Balousek
This reconstructed mound at Aztalan may have been the home site of a chief.
© Kristen Balousek

Lynne Goldstein, professor in the Department of Anthropology at Michigan State University, has spent 30 years studying Aztalan from burial sites, to the plaza and midden (garbage dump), and has surveyed a 70-square-mile area around Aztalan. Her primary interests have been site layout and structure.

"One thing that really struck me is that people kept pointing to Aztalan and had lots of theories about the site, but those theories were based on very little information," Goldstein says.

For nine years she conducted a systematic random survey in the surrounding area. She looked for evidence of related Mississippian sites and artifacts like shell-tempered pottery, tri angular projectile points and rectangular-shaped trench houses.

The Aztalan Indians would have shared the region's resources with Late Woodland Indians, a people indigenous to the Upper Midwest who built the effigy mounds found in the Aztalan area.

"I found over 450 sites, but they were not related to Aztalan," Goldstein says. During her studies she also learned a great deal about how people place themselves on a landscape.

"Aztalan's location is very interesting," she says. "It had a lot going for it." The inhabitants hunted, fished and farmed on the floodplain of the Crawfish River. The river here is shallow, and the people who lived here moved glacial boulders into the stream to form narrow rock barriers called weirs. Fish funneled through and sometimes were trapped by these fish weirs, remnants of which can be found today during low water. One side of the river was a wide open prairie rich with flowers and grasses. The other side was wooded providing timber for building and wildlife for hunting. The area has dozens of springs, which to Indian people are sacred entrances to the fertile underworld.

Corn, a staple food source for the Mississippian Indians, also would have grown well in the area. Birmingham calls Aztalan "Wisconsin's first farming town." And because chunkey, a game that involves throwing spears at a disc-shaped stone, was played here, it also is "Wisconsin's first sports stadium."


Aztalan's remnants were discovered in 1836 by Wisconsin settler Timothy Johnson. Soon after, Nathaniel Hyer, a Milwaukee judge, heard reports of the village and traveled on horseback to map the site. Hyer believed the village was built by Aztec descendants from the ancient Mexican city of Aztlan, thus, he named the Wisconsin site, "Aztalan." Though he did not get the spelling quite right and the Indians who settled here have no known links to Aztec culture, the name stuck and survives today.

Recently, a letter from Hyer describing Aztalan in 1838 surfaced on e-Bay. The Wisconsin Historical Society acquired it and you can see a copy online at Wisconsin Historical Society.

In 1850, author, naturalist, scientist and "The Father of Wisconsin Archaeology," Increase A. Lapham, investigated the site. At that time the property was mostly unfarmed and Lapham urged its preservation. Lapham's research results were published by the Smithsonian Institution in an 1855 landmark book titled "The Antiquities of Wisconsin, as Surveyed and Described." This was the first published book on Wisconsin archaeology.

Samuel Barrett began the first large-scale systematic excavations of Aztalan in 1919, as Director and Curator of the Milwaukee Public Museum. Barrett discovered remains of small houses, thousands of pieces of human and animal bone, food remains, storage and refuse pits, burial sites, chipped stone tools and pottery. Scattered human bones and remnants of a heavily fortified city and behemoth clay and heavy timber stockade wall were, for Barrett, evidence of likely violence in the region.

"The wall marks the largest prehistoric habitation site in Wisconsin," Birmingham attests.

Areas in the 22-acre village site at Aztalan include more than 30 watchtowers located along the stockade walls. Several less massive inner walls separate the site into an area where garbage was dumped, a housing area, a plaza that functioned as a public or ceremonial open space, and a pyramidal mound area. The flat-topped mounds were constructed in stages and sometimes were topped with a ceremonial building.

This tableau envisions what the walled city might have looked like. © Milwaukee Public Museum
This tableau envisions what the walled city might have looked like.
© Milwaukee Public Museum

In one temple, tribal members would have tended the sacred fire. Maintaining a sacred fire was common in Mississippian Indian culture.

Another large mound supported a charnel or burial house.

A conical mound precinct is located along a ridge at the western edge of the site (now located along Highway Q) with about 16 conical mounds in a line extending about a quarter mile north. Many of the mounds in this precinct marked the locations of large ceremonial posts. The mounds covered the holes where posts had formerly been set into the surface. Only the last mound – the Princess Burial – contained evidence of human burial.

The Princess Burial is one of the most unusual burial sites recorded in Wisconsin because it contained the remains of a female in her early twenties adorned with 1,978 local clam shell beads and a few beads of imported Gulf Coast marine shells. When Barrett excavated the mound, he dubbed her the "princess," but her actual status is unknown. Today, Princess Mound can be seen behind the settlers' Baptist Church that serves as the Aztalan Historical Museum.

Goldstein believes the princess is Late Woodland Indian instead of Mississippian culture. This mixture of Woodland and Mississippian artifacts continues to be one of the most confusing elements about the site for those trying to fathom its secrets.

Preservation efforts

When the site was mapped by Lapham there were 76 mounds, but only a fraction of those mounds remained by 1912. The land had been sold as cropland. Farmers hauled away soil from the pyramid mounds to level the fields and souvenir hunters dug for artifacts. Others hauled away the burned clay wall remnants known as "Aztalan Brick" to fill ruts in area roads.

Aztalan's beginnings as a park date to 1922 when a group of Jefferson County citizens purchased the few remaining conical mounds and named the site Mounds Park. The property was deeded to the Wisconsin Archaeological Society, and more land was purchased in 1927.

In 1947, the Wisconsin Legislature directed the state Conservation Commission (now known as the Department of Natural Resources) to buy the land as a historical memorial park. The commission bought 120 acres and the Wisconsin Archaeological Society and Lake Mills-Aztalan Historical Society donated their lands.

From 1949 to 1952 the Wisconsin Archaeological Survey (a group of professional archaeologists), excavated to provide technical information for various DNR restoration projects. Their excavations included the southwest and northwest mounds as well as additional houses, entrances to the site and the precise location of stockade lines. These locations were used during stockade restoration.

In 1952 Aztalan State Park opened to the public. The site was designated a National Historic Landmark in 1964 and listed in the National Register of Historic Places in 1966.

In 1960, Joan Freeman joined the Wisconsin Historical Society as Curator of Anthropology, and hired its first sizable field crew. She was the first woman to receive a Ph.D. in Anthropology in Wisconsin, specializing in archaeology. She was also the first State Archaeologist. The Society did more archaeological excavation in Wisconsin during the next 10 years (1960-1970), than had ever been done previously by any university or institution in the state. Freeman negotiated with the Department of Natural Resources for research support, and archaeologists worked at Aztalan for three years focusing on the stockade, northeast pyramidal mound and village area.

To date, archaeologists have also uncovered about 15 rectangular and circular pit house structures.

Modern research by Goldstein and UW-Milwaukee archaeologist John Richards has helped sort out data discovered during those early investigations. Goldstein also has mapped the site.

From 1976 to 1987, Goldstein, then at the University of Wisconsin-Milwaukee, led the "Crawfish and Rock River Archaeological Project," which later became the "Southeastern Wisconsin Archaeological Project." This was the beginning of the first systematic archaeological survey of the region surrounding Aztalan, and places the site in a broader context.

Goldstein and UW-Milwaukee archaeological students conducted shovel tests and excavations to try to answer questions about site organization and development. In 1984, the UW-Milwaukee excavated habitation areas of Aztalan including a large garbage midden deposited in a riverbank ravine. Richards, then a Ph.D. student of Goldstein's, directed excavations and analyzed contents of eight feet of neatly deposited layers that spanned remains from several hundred years of site occupation, from a small Woodland period farming village to the sudden emergence of the Mississippians.

"Each layer tells a story," Richards says. "One goal was to see if we could find a place in the site where there was a separation between the Late Woodland Indians and the Mississippians." Results demonstrated an initial Late Woodland-only occupation followed by a mixed Late Woodland and Mississippian use of the site.

Goldstein and Richards also wanted to assess the degree to which plowing disturbed the site. While excavating in the plaza, Richards found that much of the midden deposits were made up of solids that had eroded from different parts of the site as the occupants built houses, mounds and stockades.

Broken pieces of pottery formed the largest class of artifacts. They also found stone arrow points, animal bones and freshwater mussel shell hoes.

Richards' discoveries led him to believe that Aztalan was isolated and had little or no contact with Cahokia after Aztalan was settled. Evidence shows pottery styles changing over time at Cahokia, but those changes were not mimicked in Aztalan as would be expected if there was ongoing trade between the communities.

"I don't see a lot of continuous contact between Cahokia and Aztalan," he says. For example, most artifacts, including pottery, stone tools and ornaments mimicked Cahokian styles but were made from local materials like Baraboo pipestone from Sauk County.

"The site is a wonderful educational resource," Richards adds. "It's also a spectacular cultural resource that is extremely under-utilized." Much of the research on the site has centered on analyzing artifacts already taken from the site rather than digging new areas with a few exceptions.

In 1996 Goldstein's Michigan State University students studied the site. In the plaza area, they discovered a large, sculptured, tiered surface with 70 deep storage pits.

In 2003, with hopes of properly developing the site as a major interpretive location for Native American cultures, the Department of Natural Resources completed a new master plan for Aztalan that calls for expanding the park's area, a new visitor center, interpretive trails, a pedestrian bridge and fishing piers.

Preservation and protection is needed to ensure vandals stay away. During the solstice weekend tours, visitors found deep ruts left by a truck that had driven over grasses in a low-lying area of the park. Trash had been left along a stockade wall. Goldstein noted that vandalism had frequently been a problem during excavations at the site.

Yet, the site is protected by state and federal law and digging and artifact collecting are prohibited. The site also is considered sacred by modern Indian tribes.

What happened to them?

"We call Aztalan a place of histories and mysteries," said Tom Davies, the late Aztalan park ranger and staunch park supporter, in an interview videotaped by Wisconsin Public Television. And one great mystery is why the Indians left Aztalan.

Aztalan was inhabited from about 1000-1300 AD by Mississippian culture Native Americans. © Kenosha Public Museum Painting by Rob Evans
Aztalan was inhabited from about 1000-1300 AD by Mississippian culture Native Americans.
© Kenosha Public Museum Painting by Rob Evans

The village flourished for about three hundred years when around 1300 AD, the Aztalan Mississippians, like their relatives at Cahokia, seemingly vanished. There are no legends telling what happened and no written accounts since the Indians lacked a written language.

Mississippian culture was still active in areas that are now South and Southeastern states. The Spanish conquistador Hernando DeSoto and early French explorers described the Indians' customs and beliefs.

Birmingham says one hypothesis suggests the Mississippians left Aztalan when they ran out of resources. There is evidence in Cahokia that some people were malnourished – subsisting too much on corn and lacking a diet rich in protein. New climate models indicate that the Midwest also might have suffered a serious drought at the time. Violence in the region might also have chased them out of Aztalan.

Richards speculates that Oneota Indians moved into the area and were strong competitors for resources. Major Oneota occupation sites have been found at nearby Lake Koshkonong as well as near La Crosse and along the Mississippi River.

"The clues as to why the Mississippians left Aztalan are all around us," Birmingham says. "We are going to figure it out."

In fact, more than 80 percent of the Aztalan site has not been excavated. While some artifacts are now housed at Aztalan, many pieces are scattered throughout the area, with a large number curated at the Milwaukee Public Museum.

Saving the viewshed

From the parking lot visitors can see barns, silos and the Lake Mills water tower. It's a reminder that development may come knocking.

To address this concern, the park's 2003 master plan noted "Aztalan's archaeological treasures, Native American culture, and pristine appearance must be protected. A critical component of the site's long-term protection is educating and inspiring the public to understand its global significance."

The day-use park is mostly open prairie, with 38 of its 172 acres in oak woods. You can canoe, boat and fish in the Crawfish River, but the park does not have a boat launch.

The master plan, "calls for the protection of scenic views into and out of the site through the purchase of development rights and scenic easements. The aesthetic intent is that all development on the property blend into the landscape as unobtrusively as possible so that the magic of Aztalan remains while public knowledge of the site's amazing history increases."

A "viewshed" is defined as the natural environment that is visible from one or more viewing points. Strategies to protect these scenic views and vistas include regulating the type and intensity of nearby development, setting design requirements, planting trees and screening vegetation, setting standards for locating telecommunication towers and wind turbines, requiring underground utility wires, scenic (conservation) easements, setting sign standards and developing transportation designs.

Today, a visual buffer of farm fields predominates surrounding Aztalan State Park. Though three sides of Aztalan have been deemed Agricultural Preservation Area by the Jefferson County Agricultural Preservation and Land Use Plan (1999), residential lots could still be permitted within viewing distance of the park.

The National Historic Preservation Act of 1966 requires that agencies using federal funds consider archaeological sites in project development. Wisconsin demonstrated its leadership in 1985 by strengthening state laws to include the protection of cemeteries and other burial areas.

Critical to future preservation at the site is the Friends of Aztalan State Park group, which formed in 1994 to help the DNR raise funds, lead tours and provide an advisory board to guide research at the park. The Friends of Aztalan State Park have launched a $1 million fund drive to help build a visitors' center to house a permanent artifact collection and to tell Aztalan's story as it continues to unfold.

"The people of Aztalan did not think of themselves as individuals but as part of something larger," Birmingham says. "Places like this remind us of that."

Natasha Kassulke is creative products manager for Wisconsin Natural Resources magazine.

More information

Aztalan State Park is located on Highway Q south of I-94 near Lake Mills. The park is open daily 6 a.m. to 11 p.m. A state park vehicle admission sticker is required. Self-guided tour brochures are available at the parking lots and there are interpretive signs around the site. This is a day-use only park – no overnight camping.

View a video produced by Wisconsin Public Television at Aztalan State Park.

Pick up a copy of "Aztalan: Mysteries of an Ancient Indian Town" by Robert Birmingham and Lynne Goldstein (2005) Wisconsin Historical Society Press, paperback $14.95.

Read "Viewing the Ruins: The Early Documentary History of the Aztalan Site" by John D. Richards, Wisconsin Magazine of History, Winter 2007-08.

Visit Aztalan State Park and the Friends of Aztalan.