| BLACK SWAMP NATURAL REGION |
| BLUFFTON TILL PLAIN SECTION |
| BROWN COUNTY HILLS SECTION |
| CHICAGO LAKE PLAIN SECTION |
| CRAWFORD UPLAND SECTION |
| DRIFTLESS SECTION |
| ENTRENCHED VALLEY SECTION |
| ESCARPMENT SECTION |
| GLACIATED SECTION |
| GRAND PRAIRIE SECTION |
| KANKAKEE MARSH SECTION |
| KANKAKEE SAND SECTION |
| KNOBSTONE ESCARPMENT SECTION |
| LAKE MICHIGAN BORDER SECTION |
| MITCHELL KARST PLAIN SECTION |
| MUSCATATUCK FLATS AND CANYONS SECTION |
| NORTHERN LAKES NATURAL REGION |
| PLAINVILLE SAND SECTION |
| SCOTTSBURG LOWLAND SECTION |
| SOUTHERN BOTTOMLANDS NATURAL REGION |
| SWITZERLAND HILLS SECTION |
| TIPTON TILL PLAIN SECTION |
| VALPARAISO MORAINE SECTION |