Approximately 10,000 years ago, Illinois was in a period known as the late Pleistocene epoch. During this time, the landscape was vastly different from today, primarily shaped by the receding glaciers of the last Ice Age.
The region was largely covered by ice sheets, with the Laurentide Ice Sheet extending into parts of northern Illinois. The climate was colder and wetter, with large areas dominated by tundra and steppe environments. As the glaciers receded, the landscape began to transform, exposing new land and creating lakes and wetlands.
The ecosystem supported a variety of megafauna, including mammoths, mastodons, giant ground sloths, saber-toothed cats, and camels. These animals were part of the Pleistocene megafauna that roamed the region.
Early human inhabitants, often referred to as Paleo-Indians, were present in Illinois during this period. They were hunter-gatherers who relied on hunting large game, fishing, and gathering plants for sustenance. Evidence of their presence includes stone tools, spear points, and other artifacts found at archaeological sites.
As the glaciers melted, the landscape gradually transformed into the fertile plains and river valleys we recognize today. The formation of the Mississippi River and other waterways played a significant role in shaping the region's environment and habitats.