Lowest and Highest Points in Madison County

Lowest and Highest Points in Madison County
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%