Low Elevation
< 430 feet above mean sea level
Low Place
Illinois River
Low Quad Name
Meredosia
Low PLSS
3-32-16N-13W
Low Geology
Cahokia Alluvium, river valley
High Elevation
> 705 feet above mean sea level
High Place
2 unnamed hilltops
High Quad Name
Alexander and Jacksonville
High PLSS
3-23-14N-9W and 3-30-14N-9W
High Geology
Vandalia till uplands over Pennsylvanian Modesto Formation
Area
566.72 square miles
Total Relief
275 feet
Percent Slope
0.92%