More than 10,000 years ago, small bands of people entered Dodge County on the edge of the receding glacier. As hunters and gatherers, early native Americans followed and hunted herds of large animals and gathered food stuffs. The river systems from the south were used by early inhabitants to reach the wildlife and other resources the county provided in abundance. Numerous sites within the county show evidence of the early inhabitants including stone tools, campsites and settlements, burial and effigy mounds, garden plots and paintings and carvings on rock outcrops and stones.

It was the great glaciers of the last Ice Age that gave rise to this marshland basin. Since these early origins, it has been home to an abundant variety of fish, birds, and other marshland wildlife. Evidence indicates that man was already here when this marsh was in its infancy. Over the years, more than 265 species have been sighted here and Horicon marsh regularly attracts some of Wisconsin’s rarest birds.