Mesotrophic Lakes in Illinois
9 mesotrophic lakes in Illinois. Moderate nutrients, good water quality.
Most well-managed working lakes register as mesotrophic — the band that balances productivity with clarity. 9 lakes in Illinois sit in the mesotrophic band. About 0% are deep (50+ ft); the rest are shallower basins where watershed management keeps nutrients from pushing the system into eutrophy.
Mesotrophic lakes sit in the middle of the phosphorus and chlorophyll-a range: productive but still clear, with readings that rarely reach the EPA's poorest condition class.
| # | Lake | County | Clarity | Depth | TSI |
|---|---|---|---|---|---|
| 1 | Lake Opeka | Cook | 4 ft | - | 51 |
| 2 | Lake Calumet | Cook | 4.1 ft | - | 49 |
| 3 | Silver Lake | McHenry | 7 ft | - | 45 |
| 4 | Powderhorn Lake | Cook | 10.1 ft | - | 44 |
| 5 | Baumann Park Lake | Winnebago | 10.2 ft | - | 45 |
| 6 | Grays Lake | Lake | 3.5 ft | - | 50 |
| 7 | Catherine Lake | Lake | 7.4 ft | - | 49 |
| 8 | Cedar Lake | Lake | - | - | 46 |
| 9 | Deep Lake | Lake | - | - | 38 |
All mesotrophic lakes →Minnesota version →Wisconsin version →Michigan version →Iowa version →Ohio version →Pennsylvania version →New York version →Missouri version →Indiana version →North Dakota version →South Dakota version →Florida version →Colorado version →North Carolina version →Vermont version →Texas version →Oregon version →Arkansas version →Oklahoma version →Kansas version →Nebraska version →Nevada version →Arizona version →Idaho version →Montana version →New Mexico version →Tennessee version →Alabama version →Virginia version →Kentucky version →Utah version →Washington version →Wyoming version →Georgia version →Massachusetts version →Ontario version →Québec version →Nova Scotia version →British Columbia version →Newfoundland and Labrador version →All Illinois lakes →
Source: EPA National Aquatic Resource Surveys, 2026.