Long before people came to what we now call Wisconsin, the Ice Age shaped the land.
The lower Wisconsin River Valley looks as it does today because the glaciers covering eastern and northern Wisconsin 10,000 years ago melted away. A huge glacial lake formed at the western edge of the glacier as the melting waters pooled. This part of the river channel was cut by the force of the water draining to the southwest from the glacial lake.
Swiftly moving water carried sand and gravel from the melting glaciers, depositing it in the Lower Wisconsin River valley. The valley would be as much as 200 feet deeper without this accumulation. Today, the shallow and shifting nature of the sands limit the types of boats that can travel on this section of the river.
Geology does not tell the only story.
According to some American Indian legends, the Wisconsin River was created by a manitou, or spirit, which took the form of a giant serpent. One day the serpent traveled from his home in the great forest to the sea. While crossing over the land he made a groove that filled with water. Streams arose from the grooves of other serpents that filled in all directions, fearing the manitou. At the Wisconsin Dells, large rocks blocked the great serpent's path. He pushed his head into a crack and split the stone apart. The serpent continued on, but soon became tired. As he rested and rolled around, he widened the river channel.