Archaeologists have discovered 16 ancient canoes left behind by Indigenous people along the shore of a Wisconsin lake, in what they described as the prehistoric version of a modern-day docking station for shared electric bicycles.

The locations of the canoes were carefully mapped as archaeologists identified each of them, submerged in Lake Mendota in Wisconsin's capital city, over a period of several years, the Wisconsin Historical Society announced Wednesday.

Tamara Thomsen, the state's maritime archaeologist, discovered the first 1,200-year-old dugout canoe in Lake Mendota in 2021 and has been studying the site ever since, according to the historical society.

Thomsen said that the site lies near a network of what were once indigenous trails. They were likely not owned by individuals but shared among a community and left in those locations so that people could pick them up and use them as they traveled, the historical society said, likening the practice to community bike sharing programs that "utilize docking stations for users to store bikes between riders."

"It's a parking spot that's been used for millennia, over and over," Thomsen said.

Lake Mendota is a sprawling, 15-square-mile body of water on Madison's west side. The state Capitol building and the University of Wisconsin-Madison are located on an isthmus that runs between it and Lake Monona, a 5-square-mile lake to the east.

After the first canoe was found 24 feet below the surface of Lake Mendota in 2021, archaeologists went on to uncover the remains of a 3,000-year-old canoe, a 4,500-year-old canoe, and a 2,000-year-old canoe during their explorations the following year. Those discoveries suggested to researchers that there was probably more to the site than they expected.

Working with Sissel Schroeder, a UW-Madison professor who specializes in Native American cultures, and preservation officers with the Ho-Chunk Nation and the Bad River Band of Lake Superior Chippewa, Thomsen has now located the remains of 12 additional canoes, Thomsen said.

"The canoes give us insight into a sophisticated travel network and interconnected communities who used their incredible skills and knowledge to live and thrive on lands where we still live and thrive today. They reflect a deep relationship with the environment and the ingenuity of our ancestors," said Larry Plucinski, of the Bad River Band of Lake Superior Chippewa, in a statement. "Sharing what we learn from this project honors the innovators whose knowledge lives on and inspires new generations to feel pride for their ancestors."

Radiocarbon dating shows the oldest of the 16 canoes dates back to 5,200 years ago, making it the third-oldest canoe discovered in eastern North America, she said. The two oldest were found in Florida, with the oldest of them dating back 7,000 years, Thomsen said.

Wisconsin experienced a drought beginning about 7,500 years ago and lasting to around 1000 B.C., Thomsen said. The lake in the area where the canoes were found was probably only 4 feet deep over that period, she said, making it a good place to disembark for foot travel. The canoes likely were shared among community members and stored at designated points like the Lake Mendota site. Users would typically bury the canoes in sediment in waist- to chest-deep water so they wouldn't dry out or prevent them from freezing, Thomsen said.

Travelers may have been headed to Lake Wingra, a 321-acre lake on Madison's south side, Dr. Amy Rosebrough, the state archaeologist, said. The Madison area is part of the ancestral homeland of the Ho-Chunk Nation, which views one of the springs that feeds Lake Wingra as a portal to the spirit world, she said.

"The canoes remind us how long our people have lived in this region and how deeply connected we remain to these waters and lands," Bill Quackenbush, the Ho-Chunk's tribal preservation officer, said in a news release.

Thomsen speculated that if the drought did begin 7,500 years and archaeologists are finding canoes beneath other canoes, they may eventually find a 7,000-year-old canoe in the lake. That could mean Indigenous people that predated many of Wisconsin's tribes may have used the lake, she said.

Thomsen spends most of her days uncovering Great Lakes shipwrecks and works on the canoe project only one day per week. But she called that work the most impactful she has ever done as an archaeologist because she engages with Wisconsin tribes, learns their history and tells their stories.

"I think I've shed more tears over this," she said. "Talking with the Indigenous people, sometimes I sit here and just get goose bumps. It just feels like (the work is) making a difference. Each one of these canoes gives us another clue to the story."