Union County historian hopes to help unravel mystery of Big Sioux Township burial site

Sep 22, 2023

Eric Rosenbaum, a Union County historian, talks about his research into this North Sioux City site beside Interstate 29. Human remains from the 1800s were found there in the summer of 2014.

Eric Rosenbaum talks about his historical research into this site beside Highway 29 where human remains from the 1800s were found in North Sioux City, S.D., Thursday, June 9, 2022.

Eric Rosenbaum, a Union County historian, talks about his research into a North Sioux City site beside Interstate 29 where human remains from the 1800s were found in the summer of 2014.

NORTH SIOUX CITY -- Union County historian Eric Rosenbaum has a list of nearly three dozen people he believes could have been interred over 150 years ago in long-forgotten graves in Big Sioux Township.

A utility crew unearthed skeletal remains on July 31, 2014 along Interstate 29, near Exit 2 in North Sioux City, while laying fiber optic cable. The bones, which are undergoing further study, are thought to belong to roughly nine people who were buried sometime between 1860 and 1870.

The site, which lies in the right of way just feet from a big blue sign advertising gas stations, is not marked on any historical maps or thought to be a Native American burial ground.

"I was interested like everyone else," Rosenbaum recalled of his reaction to the discovery. "I've always been interested in local history here."

A MidAmerican utility crew unearthed skeletal remains on July 31, 2014 near Exit 2, while laying fiber optic cable. The bones, which are undergoing further study, are thought to belong to roughly nine people who were buried sometime between 1860 and 1870.

A couple of years passed and, not having heard anything further about the remains, Rosenbaum sent an email to the South Dakota State Historical Society Archaeological Research Center stating that he thought the mystery of the individuals' identities could be unraveled. Rosenbaum also provided the names of a couple of people that might be buried there. Six months later, he received a call. The Archaeological Research Center was interested in his research.

Rosenbaum began his research with the 1860 Census to find out who was living in Big Sioux Township at that time. He described its inhabitants as an "eclectic group of people," which included retired fur traders, Mormon pioneers and a variety of immigrants.

"You make a list of those folks. Then, you go to the 1870 Census and see of those folks, how many were left here," said Rosenbaum, who will discuss the graves Tuesday evening at The Pointe in Elk Point alongside Katie Lamie, the Archaeological Center's repository manager.

Rosenbaum eliminated people who disappeared from the rolls or whose noteworthy deaths made local newspapers, such as The Sioux City Journal, which was founded in 1864. He also read numerous books written about the fur trade of the upper Missouri River and turned to state historical societies and museums for information.

Rosenbaum

"I've acquired letters from some people here in the Big Sioux Township. You can kind of use things like that to verify they were here and what they were doing. But, it is a process of elimination," he said. "If The Sioux City Journal reported somebody died, Bingo! That's a possibility. Then, you go and figure out where they are buried."

Rosenbaum's list contains 33 names. Ten of those people he calls "high probabilities" to have been buried there. William Kenceleur, an immigrant from Quebec who worked for Pierre Chouteau, Jr.'s fur trading company; Francis LaCharite, a bourgeois at Fort Vermillion; and Henry Aungie, a clerk, interpreter and guide for the American Fur Company, are among them.

Rosenbaum speculates that the graves may belong to Aungie, his wife Mary and their family members. He said Aungie had "significant history" in Sioux City and at Fort Vermillion No. 2, which was four miles west of Elk Point.

A military button dating to 1820 and a bone rosary are artifacts recovered from the site that point to Aungie, according to Rosenbaum. He said the military button, an artillery one, could've come from the Blackhawk War of 1832. He said it's possible that Aungie participated in that war as a guide, as he was in the Prairie du Chien, Wisconsin, area at that time.

"As a fur trader, one of the biggest articles that they could trade with a chief from a tribe was something called a chief's coat. All it is is a military coat that looks like any other military coat. It would be blue or red with a bunch of brass buttons on it," Rosenbaum said. "That was a highly prized possession of the chief of the tribe. They would trade upwards of 20 or 30, sometimes as many as 50, buffalo robes for one of these. It gave them a huge status symbol when they went back to their villages."

Eric Rosenbaum, a Union County historian, talks about his research into this North Sioux City site beside Interstate 29. Human remains from the 1800s were found there in the summer of 2014.

Rosenbaum said the forts' clerks would also occasionally wear a military coat because it gave them status when trading with the tribes.

"One theory would have (Aungie) wearing a military coat, possibly related to the Blackhawk War, or he might have been wearing a clerk's coat, which would have been a status symbol for him," he said.

Some of the remains belong to infants, which Rosenbaum said are going to be "really tough to identify short of using DNA." He said the infants might not of even had names when they were buried.

"The science is going to solve this. I come up with the theories. The (Archaeological Research Center) uses the science," he said. "With the exception of the infants, I'm fairly confident that we will identify the majority of the adults."

If and when that day comes, Rosenbaum said it will be "bittersweet."

"The journey has been so much fun, learning the history of this area. I knew there was a significant history, but not to the extent that we have," he said.

WHAT: Presentation on the fur trade and the abandoned graves of Big Sioux Township, discovered in 2014.

WHEN: 7 p.m. Tuesday

WHERE: The Pointe, 100 Truman Lane, Elk Point

MORE: Eric Rosenbaum, a Union County historian, and Katie Lamie, Repository Manager for the South Dakota Archaeological Center, will discuss their research of the historic burial site found along the I-29 right of way in North Sioux City.

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