As with past traditions, archaeologists know little about the religion or political systems of the Woodland people. Archaeologists have found man-made mounds around the state that have been dated to this time. Exactly why they were made is unknown. They may have been made as part of a ceremony or to mark territories or trails. Often they are located on prominent ridges that would have been visible from a distance, and may have marked the margins of territories.
Some of the mounds contain burials, others do not. Some of the burials were placed in the mounds during construction and some were placed in the mounds after their completion. Groups of people may have gathered annually or every few years to build mounds and bury those members of their community who had passed away since the last gathering.
Mounds were made in a variety of shapes. Early mounds were conical (circular). Later effigy mounds were made in the shapes of animals such as bears, panthers, birds and other animals. Effigy mounds are unique to a small area of the country. They are only found in southwestern Wisconsin, southeastern Minnesota, and northeastern Iowa.