Big Stone County Lake Quality
Minnesota, 8 lakes, average grade F (Algae-prone)
Only 8 lakes in Big Stone 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 F — the most-stressed bracket in our rubric. Most monitored lakes here show persistent nutrient loading and algal pressure.
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. Big Stone Lake (F) is the cleanest in the county.
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Quick Answers for Big Stone County
Planning a trip? Check special fishing regulations for Big Stone Lake — or browse the full Minnesota regulations index.
Fishing in Big Stone County
DNR Reports (9)
Minnesota DNR LakeFinder resources for lakes in Big Stone County. browse all reports →
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Long TomFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — OtreyFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — East ToquaFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — BarryFisheries Lake Survey · MN DNR LakeFinder
- —Public Water Access Sites — BarryPublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — East ToquaFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — East ToquaPublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — Long TomFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Long TomPublic Water Access Sites · MN DNR LakeFinder
All Lakes in Big Stone County
8 lakes · 2 graded, 6 not rated2 graded lakes · 6 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Max Depth | Access |
|---|---|---|---|---|---|---|---|---|
| 1 | FBig Stone LakeBig Stone | F | 3.9 ft | 217 µg/L | 35.6 µg/L | No recent samples | No recent samples | ✓ Public |
| 2 | FEast Toqua LakeBig Stone | F | 1.6 ft | 703 µg/L | 33.7 µg/L | No recent samples | 9 ft | ✓ Public |
| NRUnnamed LakeBig Stone | NR | 6.9 ft | 167.5 µg/L | 11.6 µg/L | No recent samples | No recent samples | Carry-in | |
| NRUnnamed LakeBig Stone | NR | 2 ft | 518.5 µg/L | 44.4 µg/L | No recent samples | 15 ft | ✓ Public | |
| NRBarry LakeBig Stone | NR | 0.8 ft | 348 µg/L | 149 µg/L | No recent samples | 8.8 ft | ✓ Public | |
| NRCup LakeBig Stone | NR | 5.1 ft | No recent samples | No recent samples | No recent samples | No recent samples | ✓ Public | |
| NROtrey LakeBig Stone | NR | 1 ft | 431 µg/L | 156 µg/L | No recent samples | 8 ft | Carry-in | |
| NROlson LakeBig Stone | NR | 0.7 ft | 774 µg/L | 384 µg/L | No recent samples | No recent samples | Carry-in |
NR = not rated: the monitoring record does not meet the evidence bar for a grade. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
Lake Match
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Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of graded lakes that fit, with the water quality behind each one.
Other Counties in Minnesota
See how Big Stone County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 39 states and 2 Canadian provinces.
Source: EPA National Aquatic Resource Surveys, 2026.