More than 13,000 years ago, prehistoric hunter-gatherers traveled these hills and found what they needed to sustain nomadic bands. They were followed by Archaic and Woodland cultures that formed more permanent camps and cultivated crops, and social complexity increased with the Mill Creek and Oneota peoples, along with changes in lodgings, pottery, and cultural practices. In Stone Park, Clovis spear-points and other evidence connect the area to some of the earliest known people in North America, while later campsites, burial sites, middens, tools, pottery, and traded objects show long occupation and exchange across the region. Stone Park is most closely associated with the Yankton Sioux Nation, the last people to inhabit these lands, and by 1804 the Lewis & Clark Expedition met Native American tribes across the Missouri River in Nebraska. By 1900, the Sioux, the last remaining Native Americans in Iowa, had ceded their land to the United States.