Mercer County Lake Quality
North Dakota, 1 lake, measured by ND DEQ
Mercer County has 1 monitored lake — 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. Every one of those lake carries recent nutrient and algae readings, so the county-level summary covers the full set rather than a monitored subset. The county's readings sit in the middle of the North Dakota range, with one or two lakes pulling the average up or down depending on year.
The county's lakes lean shallow, which makes the readings sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest measured lake is Harmony Lake.
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Quick Answers for Mercer County
Planning a trip? Check special fishing regulations for Harmony Lake — or check the official North Dakota fishing regulations.
All Lakes in Mercer County
1 lake1 lake ranked on readings
| # | Lake | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|
| 1 | Harmony LakeMercer | 2.3 ft | 67.5 µg/L | 8.4 µg/L | No recent samples | ✓ Public |
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Source: the North Dakota Department of Environmental Quality. See data sources.