Eutrophic Lakes Across 12 States
High nutrients, frequent algae, reduced clarity. 2,005 lakes (37% of all graded lakes).
Eutrophic lakes — TSI 50 to 70 — are nutrient-rich and productive, with persistent summer algal communities that drive visible reductions in clarity. These conditions are not failures; they reflect a lake doing what nutrient-loaded waters do. 2,005 the 12 states LakeQuality covers lakes register as eutrophic. Only 7% are deep — eutrophy correlates with shallowness, agricultural watersheds, and the kind of nutrient-input history that takes decades to shift.
Eutrophic lakes typically grade C or D on the LakeGrade rubric. The same nutrient richness that defines the trophic class drives the lower grade.
| Lake | County | State | Grade | Clarity | Depth |
|---|---|---|---|---|---|
| Stone Lake | St. Louis | MN | B | - | - |
| Kettle Lake | Carlton | MN | B | - | - |
| Winkle Lake | St. Louis | MN | B | - | - |
| Erie Lake | Meeker | MN | B | - | 34 ft |
| Campers Lake | Lake | MN | B | - | 2.5 ft |
| Boot Lake | Vilas | WI | B | - | 19 ft |
| Big Twin Lake | Waushara | WI | B | - | 13 ft |
| Unnamed Lake | Douglas | WI | B | - | 6 ft |
| Unnamed Lake | Washburn | WI | B | - | - |
| L St Germain Lk Site K @ S. Bay Lake | Vilas | WI | B | - | 53 ft |
| Lk Superior Lake | Douglas | WI | B | - | - |
| Little Wood Lake | Burnett | WI | B | - | 23 ft |
| Delavan Lake | Walworth | WI | B | - | 52 ft |
| Dunes Lake Just Us of Outlet | Door | WI | B | - | - |
| Inlet To Dunes Lake | Door | WI | B | - | 1 ft |
| East Wetland Inlet To Lake Ree | Bayfield | WI | B | - | - |
| Indian School Lake | Sawyer | WI | B | - | 6 ft |
| Wiley Lake | Bayfield | WI | B | - | - |
| Two Bear Lake | Rusk | WI | B | - | 35 ft |
| Whitefish Bay Shore Lake | Chippewa | MI | B | - | - |
| Patterson Lake | Stark | ND | B | - | 24.8 ft |
| Lemay Lake | Dakota | MN | B | 6.9 ft | 15.5 ft |
| Fish Lake | Washington | MN | B | 5 ft | - |
| Jessie Lake | Beltrami | MN | B | 4.6 ft | 35 ft |
| Chevans Lake Deep | Cook | MN | B | 1.9 ft | - |
| Chippewa Flowage Lake | Sawyer | WI | B | 6.9 ft | 92 ft |
| Table Rock Lk. by Tate Rd Lake | Taney | MO | B | 3.9 ft | - |
| Loto Upstream of Dam Lake | Miller | MO | B | 6.7 ft | - |
| Table Rock L. Lake | Stone | MO | B | 4.4 ft | - |
| Loto Lake | Camden | MO | B | 7.2 ft | - |
| Loto Lake | Camden | MO | B | 6.9 ft | - |
| Loto Lake | Camden | MO | B | 6.7 ft | - |
| Horseshoe Lake | Isanti | MN | B | 3.5 ft | - |
| Big Lake | Stearns | MN | B | 6.9 ft | 42 ft |
| Blackhawk Lake | Dakota | MN | B | 7.5 ft | 12 ft |
| Arrowhead Lake | Crow Wing | MN | B | 6.9 ft | 13 ft |
| Sand Hill Lake | Polk | MN | B | 6.9 ft | 17 ft |
| Elbow Lake | Cook | MN | B | 3.7 ft | 9 ft |
| Upper Twin Lake | Hubbard | MN | B | 6.9 ft | 12 ft |
| Toad Lake | Becker | MN | B | 7 ft | 29 ft |
| Sarah Lake | Polk | MN | B | 7.7 ft | 27 ft |
| Hoffman Lake | Isanti | MN | B | 3.7 ft | - |
| Minerva Lake | Clearwater | MN | B | 7 ft | 16 ft |
| Beseau Lake | Becker | MN | B | 7.7 ft | 27 ft |
| Horseleg Lake | Isanti | MN | B | 3.6 ft | - |
| Waverly Lake | Wright | MN | B | 6.9 ft | 70.5 ft |
| Shoepack Lake | St. Louis | MN | B | 4.6 ft | 24 ft |
| Kittleson Lake | Polk | MN | B | 7.1 ft | - |
| Magda Lake | Hennepin | MN | B | 14.1 ft | - |
| Blackbird Lake | Becker | MN | B | 7.5 ft | - |
| Beaver Hut Lake | Lake | MN | B | 3.4 ft | 12 ft |
| West Sturgeon Lake | Itasca | MN | B | 4.1 ft | 31 ft |
| Little Wolf Lake | Cass | MN | B | 7 ft | 24 ft |
| Iron Lake | Cook | MN | B | 4.9 ft | 19 ft |
| Middle Mcdougal Lake | Lake | MN | B | 3.6 ft | 7 ft |
| Little Iron Lake | Cook | MN | B | 4.2 ft | 18 ft |
| Central Mystic Lake | Scott | MN | B | - | - |
| Lawrence Lake | Marquette | WI | B | 6.7 ft | 14 ft |
| Rush Lake | Vilas | WI | B | 5 ft | 7 ft |
| Crescent Lake | Polk | WI | B | 4.5 ft | 43 ft |
| Eagle Spring Lake | Waukesha | WI | B | 4.3 ft | 8 ft |
| Lake of the Falls | Iron | WI | B | 5.2 ft | 23 ft |
| East Twin Lake | Marquette | WI | B | 3.3 ft | 8 ft |
| Hiawatha Lake | Vilas | WI | B | 4 ft | 58 ft |
| Shoe Lake | Manitowoc | WI | B | 7 ft | 34 ft |
| Black Brook Flowage Lake | Polk | WI | B | 10.5 ft | 23 ft |
| Clarey Lake | Polk | WI | B | 4.3 ft | 49 ft |
| Van Zile Lake | Forest | WI | B | 5.4 ft | 17 ft |
| Black Hawk Lake | Iowa | WI | B | 5 ft | 42 ft |
| Patrick Lake | Adams | WI | B | 5 ft | 21 ft |
| Clay Lake | Bayfield | WI | B | 3.5 ft | 45 ft |
| Mckenzie Lake | Polk | WI | B | 7 ft | 25 ft |
| Lake Thirty | Barron | WI | B | 4.8 ft | 27 ft |
| Cruson Slough Lake | Richland | WI | B | 7.6 ft | - |
| Opeka Lake | Cook | IL | B | 3.9 ft | - |
| One Horse Gap Lake | Pope | IL | B | 4 ft | - |
| Tecumseh Lake | Hardin | IL | B | 3.6 ft | - |
| Grays Lake | Lake | IL | B | 3.5 ft | - |
| Lily Lake | McHenry | IL | B | 3.3 ft | - |
| Catherine Lake | Lake | IL | B | 7.4 ft | - |
| Pentwater Lake Northwest Basin; Pentwater Township | Oceana | MI | B | 7 ft | - |
| White Lake Middle Basin; Fruitland Township | Muskegon | MI | B | 7 ft | - |
| Christiana Lake Central Basin; Ontwa Township | Cass | MI | B | 7 ft | - |
| Spectacle Lake | Chippewa | MI | B | - | - |
| Milan Lake North | Sullivan | MO | B | - | - |
| Lake Ashtabula | Barnes | ND | B | 3.4 ft | 42.8 ft |
| Clark Lake | Stutsman | ND | B | 10 ft | 21.9 ft |
| Jamestown Reservoir | Stutsman | ND | B | 7.2 ft | 36.2 ft |
| Pheasant Lake | Dickey | ND | B | 3.6 ft | 19.1 ft |
| Blacktail Dam Lake | Williams | ND | B | 7.2 ft | 36.3 ft |
| Lake Audubon | McLean | ND | B | 4.7 ft | 59.4 ft |
| Horseshoe Lake | Chisago | MN | C | 4.6 ft | 53 ft |
| Bass Lake | Washington | MN | C | 6.5 ft | - |
| Schram Lake | Beltrami | MN | C | 3.9 ft | - |
| Green Lake | Chisago | MN | C | 6 ft | 32 ft |
| Crystal Lake | Dakota | MN | C | 7 ft | 37 ft |
| O'Dowd Lake | Scott | MN | C | 5.5 ft | 22 ft |
| Simian Lake | St. Louis | MN | C | 3.9 ft | - |
| Spruce Lake | Carlton | MN | C | 2.3 ft | - |
| Rice Portage Lake | Carlton | MN | C | 1.3 ft | - |
Showing 100 of 2,005 eutrophic lakes.
Frequently Asked Questions
What is an eutrophic lake?
High nutrients, frequent algae, reduced clarity. There are 2,005 eutrophic lakes across the 12 states LakeQuality covers, representing 37% of all graded lakes.
Can you swim in eutrophic lakes?
Eutrophic lakes may have algae blooms that make swimming inadvisable at times. Check for algae advisories before swimming.
Source: EPA National Aquatic Resource Surveys, 2026.