Lake Butte des Morts
Winnebago County, Wisconsin8,581 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Lake Butte des Morts. Here is what has been measured.
- Impaired · Cause unknown
- 5 aquatic invasives
- 9 ft max depth
- Public access
- Limited data
Lake Butte des Morts in Winnebago County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2.3 ft visibility. Maximum depth: 9 ft. Surface area: 8581 acres.
Wisconsin DNR rates Panfish, Northern Pike, Sturgeon, and Catfish as abundant on Lake Butte des Morts. DNR survey details →
Lake Butte des Morts is a 8,581-acre lake in Winnebago County, Wisconsin with a maximum depth of 9 feet. The lake supports 8 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 12 public boat landings.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-05-27. Methodology: how these readings are compared.
What Lake Butte des Morts is good for
From access and monitoring records, not editorial picks.
- Boat launch12 documented ramps
- Fishing8 species recorded
- Big water8,581 acres
Swimming conditions
No readingRecreation use not supported
Nutrient and algae readings are not a swimming clearance. Lake Butte des Morts is listed impaired under Clean Water Act §303(d) (IR 5) for cause unknown, nutrients (phosphorus, nitrogen), turbidity. Check local advisories before you swim.
Whether Lake Butte des Morts is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lake Butte des Morts
These are the measurements Wisconsin DNR publishes for Lake Butte des Morts, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2.3 ft of visibility. TSI 65.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 65 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Lake Butte des Morts
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Lake Butte des Morts typically sits around 52°F at the surface in October. Summer average is about 75°F. Usually warmest in Jul (about 76°F) and coldest in Oct (about 52°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (52°F) to its warmest (76°F).
Typical surface water temperature by month, from 44 field readings (2024–2026) via the EPA Water Quality Portal. See the full Lake Butte des Morts water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Lake Butte des Morts — clouds, ice, or an off-season gap in coverage. The most recent reading was high (912,011 cells/mL) on July 18, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Wisconsin DNR rates Panfish, Northern Pike, Sturgeon, and Catfish as abundant on Lake Butte des Morts.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Lake Butte des Morts’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 31 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Lake Butte des Morts covering fish populations, stocking, water quality, and management. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2023Sunset Bay (Lake Butte des Morts) spring shocking survey, 2023Spring Shocking Survey · WI DNR · 2023 (PDF)
Lake Details
Max depth
9 ft
Surface area
8,581 acres
Public access
Yes
Listed by Wisconsin DNR
Recreation & Access
- Stearns ParkPublic
- Mill StreetPublic
- Grundman ParkPublic
- Asylum Point ParkPublic
- Butte Des Morts VillagePublic
- Lake Butte des MortsPublic
Showing 6 of 12 documented landings from the USGS National Boat Ramps inventory.
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Lake Butte des Morts
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Top-rated places to stay near Lake Butte des Morts
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Fish Species
Click a species to see every lake where it is documented.
Fishing Lake Butte des Morts
- → Lake Butte des Morts fishing: DNR survey catch rates, species & stocking
- → Lake Butte des Morts fishing forecast & best times (species outlook + 14-day solunar calendar)
- → Lake Butte des Morts fishing regulations (limits, seasons, special rules)
- → Is it safe to eat fish from Lake Butte des Morts? (mercury & PFAS guide)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: Stable
Based on 5 years of monitoring (2020–2025).
Water clarity
Stable5 years
EPA Impairment Status
Lake Butte des Morts is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit WI10000955 · Official waterbody report
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Lake Butte des Morts under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 2 facilities have a reported Clean Water Act violation in the past three years.
- Oshkosh Wastewater Treatment PlantOshkosh · 3.5 mi away · NPDES WI0025038MajorRecent violation
- Butte Des Morts Consolidated Sd 1Winneconne · 3.8 mi away · NPDES WI0032492Recent violation
- Michels Materials Fl&B Sheppard QuarryOshkosh · 1.3 mi away · NPDES WI0058564
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Winnebago County
Frequently asked questions about Lake Butte des Morts
Where is Lake Butte des Morts?
- Lake Butte des Morts is a lake in Winnebago County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Lake Butte des Morts?
- Lake Butte des Morts in Winnebago County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2.3 ft visibility. Maximum depth: 9 ft. Surface area: 8581 acres.
Is Lake Butte des Morts safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Lake Butte des Morts is listed impaired under Clean Water Act §303(d) (IR 5) for cause unknown, nutrients (phosphorus, nitrogen), turbidity. Check local advisories before you swim.
What is the water temperature of Lake Butte des Morts?
- Lake Butte des Morts typically sits around 52°F at the surface in October, from 44 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Lake Butte des Morts?
- Lake Butte des Morts has a maximum depth of 9 feet. The lake covers 8581 acres.
What fish are in Lake Butte des Morts?
- Fish species found in Lake Butte des Morts include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye, Sturgeon, Catfish. Lake Butte des Morts is located in Winnebago County, Wisconsin.
What did the DNR fisheries survey find at Lake Butte des Morts?
- Wisconsin DNR rates Panfish, Northern Pike, Sturgeon, and Catfish as abundant on Lake Butte des Morts. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Lake Butte des Morts’s water-quality measurements separately, and the water-quality trend over 5 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Does Lake Butte des Morts have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Lake Butte des Morts (clouds, ice, or an off-season gap). The most recent reading was high (912,011 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Lake Butte des Morts?
- Lake Butte des Morts has 12 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Stearns Park, Mill Street, Grundman Park, Asylum Point Park, among others. Public access is listed as yes.
Can I fish at Lake Butte des Morts?
- Lake Butte des Morts has 12 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore Lake Butte des Morts across LakeQuality
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Where this data comes from
48 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX48 samples · 2020–2026
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory