sentences:  According to the US Census Bureau, the county has a total area of , of which is land and (0.9%) is water.Macon County is primarily flat, as is most of the state and all of the surrounding counties, the result of geological activity during the Pleistocene epoch.During the Illinoian Stage of the Pleistocene, the Laurentide Ice Sheet covered about 85 percent of Illinois, including the Macon County area.