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Pink and orange afterglow over the treeline on Slim Lake after sunset

Updated August 2026

The State of Minnesota's Lakes 2026

Of 2,333 lakes in Minnesota, 48.8% sit in EPA's favourable condition classes for nutrients and algae and 30.7% in its poorer ones. Rainy Lake is the cleanest; 1,630 lakes (69.9%) are on an official impaired-waters list.

Data Report

2,333
Monitored lakes sampled
C
Average readings
48.8%
low nutrient and algae readings
69.9%
On impaired list

Minnesota nutrient and algae readings

Cleanest lakes in Minnesota

Cleanest combined nutrient and algae readings, 2026.

  1. 1.Rainy Lake — Cass County13.9 ft clarity · 12 µg/L P · 2 µg/L chl-a
  2. 2.Crane Lake — Otter Tail County9.0 ft clarity · 15 µg/L P · 6 µg/L chl-a
  3. 3.Lobster Lake — Douglas County13.0 ft clarity · 21 µg/L P · 4 µg/L chl-a
  4. 4.East Fox Lake — Crow Wing County16.4 ft clarity · 10 µg/L P · 3 µg/L chl-a
  5. 5.Deep Portage Lake — Cass County15.4 ft clarity · 9 µg/L P · 2 µg/L chl-a
  6. 6.Clearwater Lake — Cook County29.0 ft clarity · 4 µg/L P · 1 µg/L chl-a
  7. 7.Clearwater Lake — Wright County9.8 ft clarity · 22 µg/L P · 6 µg/L chl-a
  8. 8.Clearwater Lake — Clearwater County10.0 ft clarity · 16 µg/L P · 3 µg/L chl-a
  9. 9.Lower Hay Lake — Crow Wing County18.5 ft clarity · 13 µg/L P · 3 µg/L chl-a
  10. 10.Latoka Lake — Douglas County19.0 ft clarity · 11 µg/L P · 2 µg/L chl-a

Highest measured algae

Highest measured chlorophyll-a (algae) concentration.

  1. 1.Olson Lake — Big Stone County384 µg/L chlorophyll-a
  2. 2.Cowley Lake — Hennepin County344 µg/L chlorophyll-a
  3. 3.Domeier Lake — Brown County332 µg/L chlorophyll-a
  4. 4.Unnamed Lake — Brown County300 µg/L chlorophyll-a
  5. 5.Alice Lake — Otter Tail County254 µg/L chlorophyll-a
  6. 6.Maria Lake — Carver County250 µg/L chlorophyll-a
  7. 7.Uhlenkolts Lake — Stearns County205 µg/L chlorophyll-a
  8. 8.Talcot Lake — Cottonwood County193 µg/L chlorophyll-a
  9. 9.Fountain Lake — Wright County174 µg/L chlorophyll-a
  10. 10.Clear Lake — Stevens County171 µg/L chlorophyll-a

Trending lakes

Improving

  1. 1.Rainy Lake — Cass County
  2. 2.Crane Lake — Otter Tail County
  3. 3.East Fox Lake — Crow Wing County
  4. 4.Deep Portage Lake — Cass County
  5. 5.Lower Hay Lake — Crow Wing County
  6. 6.Big Lake — Carlton County
  7. 7.Pelican Lake — Crow Wing County
  8. 8.Birch Lake — Ramsey County

Declining

  1. 1.Round Lake — Itasca County
  2. 2.Horseshoe Lake — Stearns County
  3. 3.Long Lake — Stearns County
  4. 4.Long Lake — Kandiyohi County
  5. 5.Long Lake — Hennepin County
  6. 6.Clear Lake — Meeker County
  7. 7.Clear Lake — Waseca County
  8. 8.Clear Lake — Jackson County

Impaired waters in Minnesota

1,630 lakes appear on the EPA/state 303(d) impaired-waters list (579 formally listed, 1,252 with a cleanup plan/TMDL).

Mercury · 1199Nutrients (phosphorus, nitrogen) · 573Impaired biota (cause unknown) · 172Salinity / chlorides · 69PFAS · 22PCBs · 10Pesticides · 2Turbidity · 1

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Minnesota Lake Trips

Where to stay at Minnesota's top lakes, each with its readings

Lakes near Minneapolis

Cleanest lakes within 50 miles of Minneapolis

Lakes near St. Paul

Cleanest lakes within 50 miles of St. Paul

Lakes near Duluth

Cleanest lakes within 50 miles of Duluth

Lakes near Rochester

Cleanest lakes within 50 miles of Rochester

Lakes near Brainerd

Cleanest lakes within 50 miles of Brainerd

Lakes near St. Cloud

Cleanest lakes within 50 miles of St. Cloud

Readings combine total phosphorus, total nitrogen, chlorophyll-a, and turbidity from the EPA Water Quality Portal and state agencies. See the full methodology, the national State of America’s Lakes report, or all Minnesota lakes.

Cite this report: LakeQuality, “The State of Minnesota's Lakes 2026”.