Native Americans, in the Hopewell period, buried their dead in earthen mounds, accompanied by grave goods that displayed their status and possibly their religious and social leadership.

Grave goods discovered in Hopewell mounds include copper from Lake Superior, sea shells from the Gulf of Mexico, mica from the Appalachian Mountains, and obsidian from the region of what is now Yellowstone National Park.

It is believed that the Hopewell Interaction Sphere had extensive trading relationships that enabled them to transfer large quantities of high-status goods across wide sections of the North American continent.

Archeologists conjecture that the Iowa River, shifting its course frequently during the following two millennia and spreading alluvial silt over its path, may have flooded or buried the site.

In the late 1800s, the Toolesboro Mound Group was inexpertly excavated by the Davenport Academy of Natural Sciences, which recovered some artifacts.

In 1966, the Toolesboro Mound Group was listed as a National Historic Landmark, and in 1969 a small visitor center and parking lot were built near the site.