Illinois Counties, Ranked by Slope
Rank, county, average percent slope
- Jo Daviess, 4.25
- Pope, 3.76
- Hardin, 3.61
- Calhoun, 3.55
- Union, 3.15
- Johnson, 3.01
- Carroll, 2.54
- Stephenson, 2.29
- Jackson, 2.25
- Jersey, 2.17
- Brown, 2.13
- Schuyler, 2.00
- Alexander, 1.97
- Fulton, 1.91
- Pike, 1.90
- Peoria, 1.82
- Putnam, 1.77
- Monroe, 1.74
- Winnebago, 1.73
- Ogle, 1.71
- Randolph, 1.67
- Saline, 1.51
- Rock Island, 1.50
- Marshall, 1.47
- Adams, 1.41
- Gallatin, 1.36
- Greene, 1.36
- Mercer, 1.35
- Knox, 1.33
- Scott, 1.32
- Massac, 1.26
- McHenry, 1.24
- Bureau, 1.23
- Tazewell, 1.22
- Edwards, 1.21
- Woodford, 1.19
- Williams, 1.19
- Hancock, 1.17
- Clark, 1.14
- McDonough, 1.13
- Henry, 1.11
- Boone, 1.07
- Hamilton, 1.07
- Kane, 1.06
- Henderson, 1.04
- La Salle, 1.03
- Lake, 1.03
- St. Clair, 0.99
- Menard, 0.98
- Cass, 0.96
- Warren, 0.96
- Wabash, 0.96
- Pulaski, 0.96
- Lee, 0.95
- Stark, 0.95
- Jefferson, 0.95
- Bond, 0.93
- Madison, 0.93
- Morgan, 0.92
- White, 0.91
- Crawford, 0.91
- Vermilion, 0.89
- Kendall, 0.89
- Shelby, 0.88
- Du Page, 0.88
- Fayette, 0.87
- Macoupin, 0.86
- Franklin, 0.85
- Will, 0.84
- Montgomery, 0.84
- Lawrence, 0.84
- Marion, 0.84
- Coles, 0.84
- Whiteside, 0.82
- Edgar, 0.79
- Wayne, 0.79
- Richland, 0.77
- McLean, 0.75
- Effingham, 0.75
- De Kalb, 0.74
- Perry, 0.73
- Cumberland, 0.73
- Clinton, 0.72
- Washington, 0.71
- Clay, 0.68
- Logan, 0.67
- Jasper, 0.65
- Cook, 0.64
- De Witt, 0.63
- Macon, 0.63
- Sangamon, 0.62
- Kankakee, 0.55
- Moultrie, 0.55
- Mason, 0.54
- Ford, 0.54
- Grundy, 0.54
- Livingston, 0.52
- Christian, 0.50
- Champaign, 0.50
- Piatt, 0.46
- Iroquois, 0.44
- Douglas, 0.40
Updated 05/27/2011 SLD