Columbia, Green Lake, and Marquette Counties were glaciated during the last ice age, and large areas were inundated with water from proglacial lakes and large meltwater rivers that occupied the valleys of the existing Wisconsin and Fox Rivers. These processes resulted in rolling upland hills, including drumlins punctuated by low-lying areas dominated by marshes underlain by lake sediment. Together with the accompanying map, this report will be of interest to those involved in land-use management and to those who are curious about how glaciers shaped these three counties in south-central Wisconsin.