Low Elevation
< 510 feet above mean sea level
Low Place
Des Plaines and Kankakee Rivers
Low Quad Name
Channahon and Wilmington
Low PLSS
3-31-34N-9E and 3-6-33N-9E
Low Geology
Cahokia Alluvium, river valley
High Elevation
> 830 feet above mean sea level
High Place
unnamed hilltop
High Quad Name
Frankfort
High PLSS
3-19-34N-13E
High Geology
Wheaton Moraine
Area
841.22 square miles
Total Relief
320 feet
Percent Slope
0.84%