St. Mary's County Lake Quality
Maryland, 4 lakes, measured by MDE
St. Mary's County has 4 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. The 4 monitored lakes in St. Mary's County carry whatever clarity, phosphorus, and chlorophyll-a readings MDE has published, shown as reported.
Most of the county's monitored lakes are shallow, under 50 feet, which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed.
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Quick Answers for St. Mary's County
Planning a trip? Check special fishing regulations for Green Holly Pond — or check the official Maryland fishing regulations.
All Lakes in St. Mary's County
4 lakes · 0 ranked on readings, 4 without enough sampling0 lakes ranked on readings · 4 without enough sampling, hidden
| # | Lake | Clarity | Phosphorus | Algae | Trophic | Max Depth | Access |
|---|---|---|---|---|---|---|---|
| Green Holly PondSt. Mary's | No recent samples | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Hall PondSt. Mary's | No recent samples | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Pond Number ThreeSt. Mary's | No recent samples | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Saint Marys LakeSt. Mary's | No recent samples | No recent samples | No recent samples | No recent samples | 24 ft | ✓ Public |
NR = no nutrient or algae reading on record. The measurements are published as the authority reports them. Where the data comes from.
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Source: the Maryland Department of the Environment. See data sources.