Directory of Power Plants in Illinois
| County | State Rank | Active Plants | Oct 2025 Generation |
| Will County, IL | # 1 | 40 | 28.5 TWh |
| Grundy County, IL | # 2 | 10 | 22.1 TWh |
| LaSalle County, IL | # 3 | 23 | 20.5 TWh |
| Ogle County, IL | # 4 | 12 | 20.0 TWh |
| Rock Island County, IL | # 5 | 7 | 16.3 TWh |
| St. Clair County, IL | # 6 | 9 | 10.8 TWh |
| De Witt County, IL | # 7 | 4 | 8.9 TWh |
| Randolph County, IL | # 8 | 5 | 6.9 TWh |
| Lee County, IL | # 9 | 12 | 5.9 TWh |
| Kendall County, IL | # 10 | 3 | 5.5 TWh |
| Jasper County, IL | # 11 | 2 | 3.7 TWh |
| Tazewell County, IL | # 12 | 10 | 3.4 TWh |
| McLean County, IL | # 13 | 15 | 3.1 TWh |
| Sangamon County, IL | # 14 | 11 | 2.8 TWh |
| Christian County, IL | # 15 | 7 | 2.8 TWh |
| Livingston County, IL | # 16 | 13 | 2.4 TWh |
| Bureau County, IL | # 17 | 11 | 2.2 TWh |
| Macon County, IL | # 18 | 6 | 2.2 TWh |
| Henry County, IL | # 19 | 6 | 1.7 TWh |
| Shelby County, IL | # 20 | 3 | 1.5 TWh |
| Logan County, IL | # 21 | 6 | 1.4 TWh |
| Mason County, IL | # 22 | 4 | 1.3 TWh |
| Ford County, IL | # 23 | 3 | 1.2 TWh |
| Vermilion County, IL | # 24 | 10 | 1.1 TWh |
| Iroquois County, IL | # 25 | 4 | 816.3 GWh |
| Williamson County, IL | # 26 | 8 | 768.4 GWh |
| Douglas County, IL | # 27 | 2 | 675.5 GWh |
| Kankakee County, IL | # 28 | 18 | 665.4 GWh |
| DeKalb County, IL | # 29 | 15 | 655.1 GWh |
| Woodford County, IL | # 30 | 3 | 651.1 GWh |
| White County, IL | # 31 | 4 | 586.8 GWh |
| DuPage County, IL | # 32 | 25 | 565.9 GWh |
| Stephenson County, IL | # 33 | 26 | 536.8 GWh |
| McDonough County, IL | # 34 | 5 | 511.2 GWh |
| Madison County, IL | # 35 | 10 | 492.2 GWh |
| Cook County, IL | # 36 | 77 | 491.7 GWh |
| Piatt County, IL | # 37 | 2 | 472.4 GWh |
| Clay County, IL | # 38 | 7 | 471.9 GWh |
| Stark County, IL | # 39 | 1 | 406.4 GWh |
| County | State Rank | Active Plants | Oct 2025 Generation |
| Perry County, IL | # 40 | 3 | 403.9 GWh |
| Lake County, IL | # 41 | 8 | 401.5 GWh |
| Morgan County, IL | # 42 | 8 | 383.0 GWh |
| Coles County, IL | # 43 | 4 | 376.2 GWh |
| Marshall County, IL | # 44 | 6 | 374.2 GWh |
| Cass County, IL | # 45 | 4 | 302.6 GWh |
| Clark County, IL | # 46 | 3 | 300.0 GWh |
| Saline County, IL | # 47 | 2 | 299.8 GWh |
| Champaign County, IL | # 48 | 12 | 256.6 GWh |
| Jersey County, IL | # 49 | 1 | 249.4 GWh |
| Fayette County, IL | # 50 | 3 | 233.2 GWh |
| Winnebago County, IL | # 51 | 23 | 188.1 GWh |
| Pike County, IL | # 52 | 4 | 100.1 GWh |
| Peoria County, IL | # 53 | 9 | 90.9 GWh |
| Montgomery County, IL | # 54 | 3 | 79.9 GWh |
| Warren County, IL | # 55 | 1 | 73.8 GWh |
| Kane County, IL | # 56 | 14 | 70.7 GWh |
| Whiteside County, IL | # 57 | 18 | 47.4 GWh |
| Scott County, IL | # 58 | 1 | 38.7 GWh |
| McHenry County, IL | # 59 | 21 | 33.2 GWh |
| Clinton County, IL | # 60 | 10 | 11.5 GWh |
| Macoupin County, IL | # 61 | 4 | 9.5 GWh |
| Jackson County, IL | # 62 | 2 | 8.9 GWh |
| Boone County, IL | # 63 | 3 | 8.1 GWh |
| Richland County, IL | # 64 | 1 | 4.4 GWh |
| Knox County, IL | # 65 | 6 | 4.4 GWh |
| Jefferson County, IL | # 66 | 1 | 4.3 GWh |
| Franklin County, IL | # 67 | 1 | 3.8 GWh |
| Fulton County, IL | # 68 | 3 | 3.8 GWh |
| Putnam County, IL | # 69 | 3 | 3.7 GWh |
| Jo Daviess County, IL | # 70 | 4 | 3.5 GWh |
| Carroll County, IL | # 71 | 1 | 3.0 GWh |
| Henderson County, IL | # 72 | 1 | 2.5 GWh |
| Adams County, IL | # 73 | 2 | 2.2 GWh |
| Brown County, IL | # 74 | 1 | 1.3 GWh |
| Marion County, IL | # 75 | 4 | 964.0 MWh |
| Monroe County, IL | # 76 | 2 | 491.0 MWh |
| Moultrie County, IL | # 77 | 1 | 245.0 MWh |
| Effingham County, IL | # 78 | 1 | 56.0 MWh |