Coles County Lake Quality
Illinois, 3 lakes, average grade F (Algae-prone)
Coles County has 3 monitored lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. 2 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. The county average is F — the most-stressed bracket in our rubric. Most monitored lakes here show persistent nutrient loading and algal pressure.
The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Paradise Lake (F); the most-stressed is Paradise Lake (F).
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Quick Answers for Coles County
Planning a trip? Check special fishing regulations for Paradise Lake — or check the official Illinois fishing regulations.
All Lakes in Coles County
3 lakes · 2 graded, 1 not rated2 graded lakes · 1 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | FParadise LakeColes | F | No recent samples | 215.5 µg/L | 42.3 µg/L | No recent samples | ✓ Public |
| 2 | FCharleston Side Channel LakeColes | F | No recent samples | 121 µg/L | 56.1 µg/L | No recent samples | ✓ Public |
| NRLake OaklandColes | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded |
NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
Lake Match
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Other Counties in Illinois
See how Coles County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..
Source: EPA National Aquatic Resource Surveys, 2026.