Massive Fields Where Native American Farmers Grew Corn, Beans and Squash 1,000 Years Ago Discovered in Michigan
The ancestors of the Menominee Indian Tribe of Wisconsin built earthen mounds to grow crops. The site could be the largest preserved archaeological field system in the eastern United States
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Hundreds of years before the arrival of the first Europeans, Indigenous farmers were growing crops like squash, corn and beans in earthen mounds they built on Michigan’s Upper Peninsula.
The mounds—created by the ancestors of the Menominee Indian Tribe of Wisconsin—likely represent the largest preserved archaeological field system in the eastern United States, according to a study published this month in the journal Science.
Archaeologists discovered the mounds in May 2023 during the brief window between winter and spring. The winter snow had melted, but the leaves had not yet appeared on the trees. They surveyed 330 acres using a drone equipped with a laser that mapped subtle features on the surface—a remote sensing technique known as lidar.
The team mapped an area that has cultural and historical importance to the Menominee. Located along the Menominee River on the Michigan-Wisconsin border, this region is known as Anaem Omot, or the “Dog’s Belly.”
The lidar uncovered a quilt-like pattern of parallel ridges that range from four to 12 inches tall. The mounds extend beyond the study area, suggesting the ancestral Menominee agricultural system was ten times larger than previously thought.
In August 2023, scientists returned to the site and took samples from three of the earthen mounds located various distances from the Menominee River. Radiocarbon dating suggests the ridges were initially constructed roughly 1,000 years ago. They were maintained and used for 600 years after that.
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The fact that the mounds still exist is unusual.
“Most field systems have been either lost or destroyed due to intensive land use across most of North America, through farming, including pastures and the cutting down of trees for urban development,” says co-author Jesse Casana, an anthropologist at Dartmouth College, in a statement.
The research gives scientists a “little window” into what pre-colonial life was like for the ancestral Menominee people, Casana adds.
During their excavations, the scientists also found several artifacts, including charcoal and fragments of broken ceramics. These discoveries suggest that the area’s Indigenous farmers may have dumped their household waste and the remnants of fires onto their fields, using them as compost. Samples taken from the mounds suggest the farmers enriched the dirt with soil from nearby wetlands.
The results indicate that ancestral Menominee people dedicated a lot of time and energy to agriculture in a remote area. The team has not found any significant settlement sites in the region—only a few small villages.
“It requires a lot of labor to create these fields, to clear the forest,” says Susan Kooiman, an anthropologist at Southern Illinois University Edwardsville who was not involved with the research, to NPR’s Nell Greenfieldboyce. “This is dense forest, now and then. To clear it, only with stone tools, is a lot of labor, a lot of work. … The amount of work, and just how far these fields extend, is beyond anything that I think people suspected was going on this far north in eastern North America.”
Scientists remain perplexed by the location of the mounds. At the time, the area was undergoing a colder climatic period called the Little Ice Age. The lower temperatures, in addition to the already short growing season on the Upper Peninsula, would have made it very difficult to grow crops, particularly corn.
And who were the ancestral Menominee farmers growing the crops for? What were they doing with their bounty? Perhaps they needed to feed a growing population, or they wanted to have a surplus in case they ran out of other foods, lead author Madeleine McLeester, an archaeologist at Dartmouth, tells Science News’ Bruce Bower. Maybe they were growing the crops for trade.
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These and other mysteries remain. But the findings in “an area where we would not expect intensive agriculture,” seem to suggest that “much of the eastern U.S. was once covered in Native American agricultural ridges,” McLeester adds.
The ridges were not a complete surprise, as the recent survey was building off similar research conducted in the 1990s. Current Menominee tribal authorities invited scientists to return and investigate the area again using more advanced technologies.
The scientists collaborated with Menominee leaders and representatives, including David Grignon, a historic preservation officer for the Menominee Indian Tribe of Wisconsin, and the late David Overstreet, an archaeologist who worked closely with the tribe for decades.
The team plans to continue working with the tribe to conduct similar surveys in the future. They hope to make additional discoveries, including ancestral Menominee villages.
The lidar survey also revealed other intriguing structures, including a circular dance ring and a rectangular building foundation that researchers suspect was once a colonial trading post. Additionally, the team found the remains of two 19th-century logging camps, looted burial mounds, burial mounds that were thought to have been destroyed in the 1970s and a burial mound on land that’s owned by a mining company.
“Lidar is a really powerful tool in any kind of forested or heavily vegetated region where the archaeology is hidden below trees—where no kind of optical imagery can see what’s underneath the tree canopy,” Casana says in the statement.
