Blue Earth County Lake Quality
Minnesota, 9 lakes, average grade F (Algae-prone)
Blue Earth County has 9 graded 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 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 Ballantyne Lake (D); the most-stressed is George Lake (F).
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Quick Answers for Blue Earth County
Planning a trip? Check special fishing regulations for Ballantyne Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Minnesota regulations index.
Fishing in Blue Earth County
DNR Reports (20)
Minnesota DNR LakeFinder resources for lakes in Blue Earth County. browse all reports →
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MadisonFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — LoonFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — GeorgeFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — EagleFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — DuckFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — CrystalFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — BallantyneFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — BallantyneFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — BallantynePublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — CrystalFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — CrystalPublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — DuckFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — DuckPublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — EagleFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — EaglePublic Water Access Sites · MN DNR LakeFinder
- —Public Water Access Sites — GeorgePublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — LoonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — LoonPublic Water Access Sites · MN DNR LakeFinder
- —Fish Stocking History — MadisonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — MadisonPublic Water Access Sites · MN DNR LakeFinder
All Lakes in Blue Earth County
9 lakes · 5 graded, 4 not rated5 graded lakes · 4 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Max Depth | Access |
|---|---|---|---|---|---|---|---|---|
| 1 | DBallantyne LakeBlue Earth | D | 2.5 ft | 72.5 µg/L | 9.2 µg/L | No recent samples | 58 ft | ✓ Public |
| 2 | DMadison LakeBlue Earth | D | 4 ft | 75 µg/L | 27.8 µg/L | No recent samples | 59 ft | ✓ Public |
| 3 | FGeorge LakeBlue Earth | F | 2.2 ft | 122.5 µg/L | 37.3 µg/L | No recent samples | 28 ft | ✓ Public |
| 4 | FCrystal LakeBlue Earth | F | 1.5 ft | 172 µg/L | 59.9 µg/L | No recent samples | 8 ft | ✓ Public |
| 5 | FDuck LakeBlue Earth | F | 2.8 ft | 105 µg/L | 31.5 µg/L | No recent samples | 25 ft | ✓ Public |
| NRUnnamed LakeBlue Earth | NR | No recent samples | No recent samples | No recent samples | No recent samples | No recent samples | ✓ Public | |
| NREagle LakeBlue Earth | NR | 1 ft | No recent samples | No recent samples | No recent samples | 9 ft | ✓ Public | |
| NRLoon LakeBlue Earth | NR | 2 ft | No recent samples | No recent samples | No recent samples | 7 ft | ✓ Public | |
| NRPorter LakeBlue Earth | NR | 1.3 ft | 140 µg/L | 73 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
Which lake suits how you actually use one?
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 Blue Earth 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.