Blue Earth County Lake Quality
Minnesota, 9 lakes, average grade D (Poor)
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. On average, Blue Earth County lakes grade D, with phosphorus loading and reduced clarity showing up across most of the dataset.
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 Unnamed Lake (B); the most-stressed is Eagle Lake (F).
Quick Answers for Blue Earth County
Planning a trip? Check special fishing regulations for Unnamed Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Minnesota regulations index.
DNR Reports (20)
Minnesota DNR LakeFinder resources for lakes in Blue Earth County. Showing 12 most recent — browse all reports →
- —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
All Lakes in Blue Earth County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Unnamed Lake | B | - | - | 21 µg/L |
| 2 | Madison Lake | D | 3.6 ft | 59 ft | 75 µg/L |
| 3 | Porter Lake | D | 1.3 ft | - | 83 µg/L |
| 4 | Eagle Lake | F | 1 ft | 9 ft | - |
| 5 | Ballantyne Lake | F | 2.5 ft | 58 ft | 91 µg/L |
| 6 | George Lake | F | 2.5 ft | 28 ft | 120 µg/L |
| 7 | Crystal Lake | F | 1.5 ft | 8 ft | 172 µg/L |
| 8 | Duck Lake | F | 2.8 ft | 25 ft | 105 µg/L |
| 9 | Loon Lake | F | 2 ft | 7 ft | - |
Source: EPA National Aquatic Resource Surveys, 2026.