Low Elevation
< 560 feet above mean sea level
Low Place
Rock River
Low Quad Name
Coal Valley
Low PLSS
4-19-17N-1E
Low Geology
Cahokia Alluvium, river valley
High Elevation
> 875 feet above mean sea level
High Place
unnamed hilltop
High Quad Name
Kewanee South
High PLSS
4-1-14N-4E
High Geology
Loess hill over thin Illinois Glasford till over Pennsylvanian Carbondale Formation
Area
817.22 square miles
Total Relief
315 feet
Percent Slope
1.11%