Cleanest Lakes in Illinois
Axehead Lake in Cook County leads the rankings with a water quality grade of A and 11.9 ft of clarity. Below are the top 50 cleanest monitored lakes in Illinois, ranked by EPA water quality score.
Ranked List
| # | Lake | County | Grade | Clarity | Phosphorus | Algae |
|---|---|---|---|---|---|---|
| 1 | Axehead Lake | Cook | A | 11.9 ft | 10 µg/L | - |
| 2 | Powderhorn Lake | Cook | A | 10.1 ft | 13 µg/L | - |
| 3 | Baumann Park Lake | Winnebago | A | 10.2 ft | 11.5 µg/L | - |
| 4 | Silver Lake | McHenry | B | 7 ft | 11 µg/L | - |
| 5 | Boulder South Lake | Perry | B | 8.8 ft | 14.5 µg/L | - |
| 6 | Wampum Lake | Cook | B | 6.9 ft | 16 µg/L | - |
| 7 | Round Lake | Lake | B | 7.4 ft | 19.5 µg/L | - |
| 8 | Big Rock Lake | Kane | B | 8.1 ft | 10 µg/L | - |
| 9 | Flatfoot Lake | Cook | B | 6.3 ft | 10.5 µg/L | - |
| 10 | Opeka Lake | Cook | B | 3.9 ft | 15.5 µg/L | - |
| 11 | One Horse Gap Lake | Pope | B | 4 ft | 17 µg/L | - |
| 12 | Glendale Lake | Pope | B | 4.8 ft | 16 µg/L | - |
| 13 | Tecumseh Lake | Hardin | B | 3.6 ft | 18 µg/L | - |
| 14 | Grays Lake | Lake | B | 3.5 ft | 18 µg/L | - |
| 15 | Calumet Lake | Cook | B | 4.3 ft | 10.5 µg/L | - |
| 16 | Lily Lake | McHenry | B | 3.3 ft | 16 µg/L | - |
| 17 | Catherine Lake | Lake | B | 7.4 ft | 27.5 µg/L | - |
| 18 | Vienna Correctional Center Lake | Johnson | C | 4.5 ft | 20 µg/L | - |
| 19 | Pounds Hollow Lake | Gallatin | C | 3.9 ft | 24 µg/L | - |
| 20 | George Lake | Rock Island | C | 4.2 ft | 22.5 µg/L | - |
| 21 | Shabbona Lake | DeKalb | C | 4.9 ft | 27.5 µg/L | - |
| 22 | Channel Lake | Lake | C | 8 ft | 34.5 µg/L | - |
| 23 | Lake of Egypt | Williamson | C | 3.2 ft | 26 µg/L | - |
| 24 | Sag Quarry East Lake | Cook | C | 5.4 ft | 30.5 µg/L | - |
| 25 | Turtlehead Lake | Cook | C | 2.8 ft | 20.5 µg/L | - |
| 26 | Sag Quarry West Lake | Cook | C | 4.2 ft | 52.5 µg/L | - |
| 27 | Olney East Fork Lake | Richland | C | 3.2 ft | 25.5 µg/L | - |
| 28 | Woods Creek Lake | McHenry | C | 3.9 ft | 45.5 µg/L | - |
| 29 | Long Lake | Lake | D | 3.4 ft | 35 µg/L | 47.6 µg/L |
| 30 | Arrowhead Lake | Cook | D | 2.1 ft | 31.5 µg/L | - |
| 31 | Bullfrog Lake | Cook | D | 1.4 ft | 40.5 µg/L | - |
| 32 | Horsetail Lake | Cook | D | 2.2 ft | 39 µg/L | - |
| 33 | Dutchman Lake | Johnson | D | 2.1 ft | 37.5 µg/L | - |
| 34 | Randolph Lake | Randolph | D | 1.7 ft | 49 µg/L | - |
| 35 | Wayne City Lake | Wayne | D | 2.1 ft | 34.5 µg/L | - |
| 36 | Tampier Lake | Cook | D | 1.7 ft | 38.5 µg/L | - |
| 37 | Poss Lake | DuPage | D | 1.2 ft | 32 µg/L | - |
| 38 | Midlothian Lake | Cook | D | 1.2 ft | 44.5 µg/L | - |
| 39 | Sparta Northwest Lake | Randolph | D | 2.6 ft | 34 µg/L | - |
| 40 | Sara Lake | Effingham | D | 2.2 ft | 48.5 µg/L | - |
| 41 | Otter Lake | Macoupin | D | 1.8 ft | 37 µg/L | - |
| 42 | Grass Lake | Lake | D | 1.4 ft | 57.5 µg/L | - |
| 43 | Jacksonville Lake | Morgan | D | 1.8 ft | 48 µg/L | - |
| 44 | Long Lake | Lake | D | 2.9 ft | 41.5 µg/L | - |
| 45 | Fox Lake | Lake | D | 1.9 ft | 43 µg/L | - |
| 46 | Petite Lake | Lake | D | 2.5 ft | 36 µg/L | - |
| 47 | Canton Lake | Fulton | D | 2.5 ft | 47.5 µg/L | - |
| 48 | Nippersink Lake | Lake | D | 1.3 ft | 44.5 µg/L | - |
| 49 | Kinmundy New Lake | Marion | D | 2.9 ft | 36.5 µg/L | - |
| 50 | Forbes Lake | Marion | D | 1.4 ft | 74 µg/L | - |