Grant County Lake Quality
Kentucky, 4 lakes, average grade C (Fair)
Only 4 lakes in Grant County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. The county average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.
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 Boltz Lake (C); the most-stressed is Nla Lake (C).
Quick Answers for Grant County
Planning a trip? Check special fishing regulations for Boltz Lake — or check the official Kentucky fishing regulations.
All Lakes in Grant County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Boltz Lake | C | - | 58 µg/L |
| 2 | Corinth Lake | C | - | 32.5 µg/L |
| 3 | Williamstown Lake | C | - | 39 µg/L |
| 4 | Nla Lake | C | 2.5 ft | 35.2 µg/L |
Other Counties in Kentucky
See how Grant County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 34 states.
Where to stay near Grant County
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Source: EPA National Aquatic Resource Surveys, 2026.