Boulders that are clearly out of place in meadows or on mountaintops. Receding glaciers deposited them.

Boulders carried long distances by the glaciers and deposited when the glacier melted. They tend to be smooth and rounded. Erratics can be found along the entire Ice Age Trail, except where it traverses parts of the Driftless Area. Some of the famous and largest ones along the Trail are in Waukesha, Waupaca and Langlade counties.

Boulders and other rock fragments transported by glacial ice from their place of origin to an area where the bedrock is different.

Seemingly out-of-place boulders carried to their current location by glacier movement.

Large boulders displaced from their natural geologic location by glaciers.

Boulders transported from their origin by a glacier, so that they are now found far from their parent rock and are now isolated amid dissimilar materials. Erratics found in Wisconsin have been transported from as far away as Minnesota, Michigan and Canada.