Map of Central Illinois
- The northern boundary: I-74 beginning at (but excluding) Danville, to Champaign. Then Highway 72 to Springfield.
- The southern boundary: West from Litchfield: Route 16, then Route 185 to Vandalia, and then Highway 70 to Marshall.
- The eastern boundary: Route 1 and 150 from Marshall to Danville (but excluding Danville).
