Glaciation significantly shaped the geology of the Interior Plains.

This process began during the late Paleozoic era when ancient seas covered much of the region, leading to the accumulation of sediments like sand, silt, and clay. Over time, these sediments compressed and formed sedimentary rock layers. Additionally, glacial activity during the last Ice Age influenced the landscape, redistributing soils and sediments. The combination of these geological processes created the flat and gently rolling terrain characteristic of the Interior Plains today.