Low Elevation
< 400 feet above mean sea level
Low Place
Mississippi River
Low Quad Name
Granite City
Low PLSS
3-12-9N-10W and3-35-3N-10W
Low Geology
Cahokia Alluvium, river valley
High Elevation
> 660 feet above mean sea level
High Place
unnamed hilltop
High Quad Name
Alton
High PLSS
3-1-6N-10W
High Geology
Thin Illinois Vandalia Till over Pennsylvanian Carbondale Formation
Area
732.09 square miles
Total Relief
260 feet
Percent Slope
0.93%