Illinois is part of the Ozark foothills. Glaciers scraped most of Illinois flat, but stopped just short of where Carbondale now exists, giving Southern Illinois a beautiful landscape full of sloping hillsides that provide adequate drainage and prevent frost from forming on the grapevines.
The soil in Southern Illinois is packed full of limestone, which is a great source of calcium for grapes. Also, the soil has a mild clay content, which allows for easy water absorption and drainage.
The climate in Southern Illinois is also ideal for growing grapes, with a warmer, longer growing season allowing the vines to become fully mature. Winters are also more mild here, than in other areas.