Eurasian Watermilfoil
Invasive SpeciesFound in 861 lakes
Eurasian watermilfoil is a submerged aquatic plant that forms dense surface-canopy mats, crowding out native vegetation and limiting boat access. Documented in 861 {{stateName}} lakes. A 861-lake footprint means Eurasian Watermilfoil prevention has shifted from "stop the spread" to "manage the new normal." Watercraft-inspection programs at boat launches and shoreline-management practices on individual lakes are doing most of the active prevention work.
A milfoil-infested lake can still grade well on water-clarity measurements — the plant itself does not cloud the water — but recreational use is meaningfully affected, and that is not captured in the underlying water-quality rubric.
Lakes with Eurasian Watermilfoil
| Lake | County | State | Grade | Depth |
|---|---|---|---|---|
| Birch Lake | Wright | MN | A | 52 ft |
| Ossawinnamakee Lake | Crow Wing | MN | A | 63 ft |
| Girl Lake | Cass | MN | A | 81 ft |
| Charlotte Lake | Wright | MN | A | 46 ft |
| Crooked Lake | Crow Wing | MN | A | 54 ft |
| Alexander Lake | Morrison | MN | A | 64 ft |
| Courthouse Lake | Carver | MN | A | 57 ft |
| Kimball Lake | Crow Wing | MN | A | 77 ft |
| West Sylvia Lake | Wright | MN | A | 97 ft |
| Pulaski Lake | Wright | MN | A | - |
| Bay Lake | Crow Wing | MN | A | 74 ft |
| White Bear Lake | Washington | MN | A | 83 ft |
| Sturgeon Lake | Pine | MN | A | 40 ft |
| East Sylvia Lake | Wright | MN | A | 78 ft |
| Sugar Lake | Wright | MN | A | 69 ft |
| Bad Axe Lake | Hubbard | MN | A | 39 ft |
| Carlos Lake | Douglas | MN | A | 163 ft |
| Ruth Lake | Crow Wing | MN | A | 39 ft |
| Su18 Lake | Cook | MN | A | - |
| Su19 Lake | Cook | MN | A | - |
| Sturgeon Lake | Pine | MN | A | - |
| Walker Bay Lake | Cass | MN | A | - |
| Agency Bay Lake | Cass | MN | A | - |
| Big Lake | Sherburne | MN | A | 48 ft |
| Kabekona Bay Lake | Cass | MN | A | 150 ft |
| Superior Lake | Cook | MN | A | - |
| Superior Lake | St. Louis | MN | A | - |
| Jane Lake | Washington | MN | A | 39 ft |
| Ls94 Lake | Lake | MN | A | - |
| Suseq32a Lake | St. Louis | MN | A | - |
| Seq044a Lake | Lake | MN | A | - |
| Suseq44a Lake | Lake | MN | A | - |
| Seq032a Lake | St. Louis | MN | A | - |
| Geneva Lake | Walworth | WI | A | 135 ft |
| Lac Courte Oreilles Lake | Sawyer | WI | A | 90 ft |
| Sunset Lake | Portage | WI | A | 55 ft |
| Parker Lake | Adams | WI | A | 36 ft |
| West Bay Lake | Vilas | WI | A | 31 ft |
| Long Lake | Waupaca | WI | A | 76 ft |
| Long Lake | Fond du Lac | WI | A | 47 ft |
| Long Lake | Iron | WI | A | 34 ft |
| Spring Lake | Waushara | WI | A | 37 ft |
| Spring Lake | Manitowoc | WI | A | 23 ft |
| Black Hawk Lake | Iowa | WI | A | 42 ft |
| Spider Lake | Vilas | WI | A | 43 ft |
| Silver Lake | Waupaca | WI | A | 17 ft |
| Silver Lake | Waukesha | WI | A | 40 ft |
| Silver Lake | Kenosha | WI | A | 44 ft |
| Silver Lake | Waushara | WI | A | 50 ft |
| Silver Lake | Vilas | WI | A | - |
Showing 50 of 861 infested lakes.
Frequently Asked Questions
How many lakes have eurasian watermilfoil?
Eurasian Watermilfoil has been documented in 861 lakes, 366 in Minnesota and 495 in Wisconsin.
Does eurasian watermilfoil affect water quality?
Invasive species can significantly affect lake ecosystems. They may alter nutrient cycling, displace native species, and change water clarity. Lakes with eurasian watermilfoil should be monitored for changes in water quality over time.
Source: EPA National Aquatic Resource Surveys, 2026.