Mattoon is a city in Coles County, Illinois, United States. The population was 18,555 as of the 2010 census. The city is home to Lake Land College and has close ties with its neighbor, Charleston. Both are principal cities of the Charleston–Mattoon Micropolitan Statistical Area.
One of the main factors determining the settlement of Mattoon and Coles County in general was the topography. Coles County straddled a timberline in the southern half and prairie in the north. The forested areas were primarily fed by two major rivers: the Embarras River in the east and the Kaskaskia in the west. The prairie, known as the "Grand Prairie", was generally wet and swampy. An early historian described the geography:
"Away from the timber to the north, the face of the country is generally quite level, broken only by long undulations. It is almost entirely prairie land in this part, and was allowed to remain uncultivated until after the opening of the railroads.