However, mounds in the shape of mammals, birds, or reptiles, known as effigies, apparently were constructed primarily by peoples in what is now known as southern Wisconsin, northeast Iowa, and small parts of Minnesota and Illinois.

Numerous federally recognized tribes have linguistic and cultural ties to the ancestral peoples who built the effigy and other earthwork mounds at the monument site.

The national monument is quite close to the town of Marquette, Iowa, and is just across the Mississippi River from the city of Prairie du Chien, Wisconsin, where ample motel and gambling-boat facilities exist.

Unlike the rest of Iowa, the Paleozoic Plateau was bypassed by the last of the Pleistocene glaciers (the Wisconsin), allowing the region's fast cutting streams to expose and carve out deep channels in the bedrock-dominated terrain.

The area is characterized by thin loess soil cover, isolated patches of glacial drift, deeply entrenched river valleys, and karst (sinkholes, caves, and springs) topography.

[8]From 1999 to 2009, Superintendent Phyllis Ewing "oversaw more than $3 million in illegal construction of boardwalks, trails and other structures that damaged irreplaceable archaeological artifacts.

"[9] She failed to conduct consultation with affiliated American Indian tribes and follow procedures of the National Historic Preservation Act and other statutes.

Munson was apparently trying to evade the proposed provisions of the Native American Graves Protection and Repatriation Act (NAGPRA), which was passed by Congress that year.

[10] The act provides for artifacts and bones to be returned or repatriated by governmental agencies and other institutions to tribes who are affiliated with the peoples who buried the items.

The government conducted a five-year investigation through the US Attorney's Office, following questions raised in 2011 by Iowa Tribe of Kansas and Nebraska member Patt Murphy.

[10] Munson was sentenced to a year of home detention, 10 weekends in jail, and paying "$108,905 in restitution for the damage he caused to the bones and a $3,000 fine.