Mary Lake
Marinette County, Wisconsin186 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Mary Lake. Here is what has been measured.
- Mesotrophic
- 38 ft max depth
- Public access
Mary Lake in Marinette County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 9 ft visibility. Phosphorus: 13.5 µg/L. Maximum depth: 38 ft. Surface area: 186 acres.
Wisconsin DNR lists Panfish as common on Mary Lake. DNR survey details →
Mary Lake is a 186-acre mesotrophic lake in Marinette County, Wisconsin with a maximum depth of 38 feet. The lake supports 3 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 2 public boat landings. Compared to the 9 other monitored lakes in Marinette County, Mary Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2023-08-28. Methodology: how these readings are compared.
What Mary Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
- Fishing3 species recorded
- Deep water38 ft surveyed max depth
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Mary Lake 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 Mary Lake
These are the measurements Wisconsin DNR publishes for Mary Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 9 ft. Phosphorus 13.5 µg/L. TSI 44.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 13.5µg/L | Good GoodFairPoor |
| 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. | 44 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Mary Lake
Answers come straight from the public measurements and survey records on this page.
Wisconsin DNR lists Panfish as common on Mary Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Mary Lake’s water-quality measurements separately, and the water-quality trend over 4 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. 2 stations on file (most recent sample 2023).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Mary Lake 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).
- 2020Timms Lake fishery summary, 2020Fisheries Survey · WI DNR · 2020 (PDF)
Lake Details
Max depth
38 ft
Surface area
186 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
7 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.4 mi
HydroLAKES / HydroSHEDS
Elevation
666 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lake Mary (East)Public
- Lake Mary (West)Public
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Mary Lake
Compare lakeside cabins, hotels, and vacation rentals near Mary Lake in Marinette County, Wisconsin — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Mary Lake
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Follow Mary Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Mary Lake
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 4 years of monitoring (2020–2023).
Water clarity
Stable4 years
Phosphorus
Stable+0.23 µg/L/yr4 years
Nearby Lakes in Marinette County
Frequently asked questions about Mary Lake
Where is Mary Lake?
- Mary Lake is a lake in Marinette County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Mary Lake?
- Mary Lake in Marinette County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 9 ft visibility. Phosphorus: 13.5 µg/L. Maximum depth: 38 ft. Surface area: 186 acres.
Is Mary Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Mary Lake?
- Mary Lake has a maximum depth of 38 feet. The lake covers 186 acres.
What fish are in Mary Lake?
- Fish species found in Mary Lake include Panfish, Largemouth Bass, Northern Pike. Mary Lake is located in Marinette County, Wisconsin.
What did the DNR fisheries survey find at Mary Lake?
- Wisconsin DNR lists Panfish as common on Mary Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Mary Lake’s water-quality measurements separately, and the water-quality trend over 4 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Mary Lake?
- Mary Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Lake Mary (East), Lake Mary (West). Public access is listed as yes.
Can I fish at Mary Lake?
- Mary Lake has 2 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 Mary Lake across LakeQuality
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Where this data comes from
46 measurements from 2 monitoring stations, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX46 samples · 2020–2023
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (2)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory