Mille Lacs County Lake Quality
Minnesota, 11 lakes, average grade B (Good)
Only 11 lakes in Mille Lacs 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. With an average grade of B, Mille Lacs County sits comfortably above the Minnesota median.
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. Outlet of Onamia Lake on the Rum River (A) is the cleanest in the county.
Quick Answers for Mille Lacs County
Planning a trip? Check special fishing regulations for Outlet of Onamia Lake on the Rum River, and the best times to fish — or browse the full Minnesota regulations index.
DNR Reports (6)
Minnesota DNR LakeFinder resources for lakes in Mille Lacs County. browse all reports →
- —Fisheries Lake Survey — OnamiaFisheries Lake Survey · MN DNR LakeFinder
- —Fisheries Lake Survey — OgechieFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Ogechie (0340)Aquatic Plant Report · MN DNR LakeFinder
- —Aquatic Plant Report — Onamia (0341)Aquatic Plant Report · MN DNR LakeFinder
- —Aquatic Plant Report — Silver (0299)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — SilverPublic Water Access Sites · MN DNR LakeFinder
All Lakes in Mille Lacs County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Outlet of Onamia Lake on the Rum River | A | - | 10 ft | 25 µg/L |
| 2 | Outlet of Ogechie Lake on the Rum River | A | - | 6 ft | 24 µg/L |
| 3 | Ml-Peterson Lake | B | 7.4 ft | 42 ft | 26.5 µg/L |
| 4 | Ml-Thains Lake | B | 5.3 ft | 42 ft | 26 µg/L |
| 5 | Ml-Se Lake | B | 7.4 ft | 42 ft | 26.5 µg/L |
| 6 | Ml-Vineland Lake | B | 7.8 ft | 42 ft | 23 µg/L |
| 7 | Ml-Malone Lake | B | 5.7 ft | 42 ft | 24 µg/L |
| 8 | Mille Lacs Lake | C | 9 ft | 42 ft | - |
| 9 | Silver Lake | F | 1 ft | - | - |
Source: EPA National Aquatic Resource Surveys, 2026.