The lake is a remnant of Glacial Lake Oshkosh approximately 12,000 years ago.
Ice blocked water from entering Lake Michigan at Green Bay, and the glacial lake ponded against ice since it had no outlet.

The Niagara Escarpment is a few miles east of Lake Winnebago.
The softer Ordovician rocks that underlie the lake have eroded away, and the stronger Silurian rocks stand as a ridge that formed the lake basin.

In 1634, the French discovered the Winnebago tribe on the shores of Green Bay, inhabiting the area stretching to Lake Winnebago.
Although "Ho-Chunk" is the people's own name for themselves, their Algonquian neighbors called them "Winnebago", which means "[people of the] stinking water".
This term was used by the Algonquians because Lake Winnebago had a strong fish odor in the summer.

The steamer B. F. Carter made a trip from the east shore to the west shore at Oshkosh every two weeks in the 1880s during the summer season.

Lake Winnebago is known for having occasional ice shoves on very windy days in March as the winter ice breaks up.
Residents have described that it "sounds like a freight train."
Buildings on the shore have been wrecked by the shoves, which are up to 25 feet high.
The lake is a remnant of Glacial Lake Oshkosh approximately 12,000 years ago. Ice blocked water from entering Lake Michigan at Green Bay, and the glacial lake ponded against ice since it had no outlet.
The Niagara Escarpment is a few miles east of Lake Winnebago. The softer Ordovician rocks that underlie the lake have eroded away, and the stronger Silurian rocks stand as a ridge that formed the lake basin.
In 1634, the French discovered the Winnebago tribe on the shores of Green Bay, inhabiting the area stretching to Lake Winnebago. Although "Ho-Chunk" is the people's own name for themselves, their Algonquian neighbors called them "Winnebago", which means "[people of the] stinking water". This term was used by the Algonquians because Lake Winnebago had a strong fish odor in the summer.
The steamer B. F. Carter made a trip from the east shore to the west shore at Oshkosh every two weeks in the 1880s during the summer season.
Lake Winnebago is known for having occasional ice shoves on very windy days in March as the winter ice breaks up. Residents have described that it "sounds like a freight train." Buildings on the shore have been wrecked by the shoves, which are up to 25 feet high.
Lake Winnebago