Mary Lake
Mary Lake in Langlade County, Wisconsin has a water quality grade of B (Good). Water clarity: 7 ft visibility. Phosphorus: 18.3 µg/L. Maximum depth: 20 ft. Surface area: 154 acres.
Wisconsin DNR lists Largemouth Bass as common on Mary Lake. DNR survey details →
- Clarity
- 7 ft
- Max depth
- 20 ft
- Area
- 154 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Mary Lake is a 154-acre mesotrophic lake in Langlade County, Wisconsin with a maximum depth of 20 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is improving over recent sampling years. The lake supports 2 documented fish species including Panfish and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 10 other monitored lakes in Langlade County, Mary Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-21. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Moderate clarity, visible to about 7 ft. Phosphorus level: 18.3 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7 ft | Not graded |
| Phosphorus | 18.3 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Mary Lake
Compare lakeside cabins, hotels, and vacation rentals near Mary Lake in Langlade 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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Wisconsin DNR lists Largemouth Bass as common on Mary Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Mary Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 7 years of monitoring is improving. 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. Monitored by volunteers since 1989. 1 station on file (most recent sample 2025).
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).
- 2024Enterprise Lake spring summary report, 2024Fisheries Survey · WI DNR · 2024 (PDF)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 20 ft |
| Surface Area | 154 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Mary LakeSemi-private
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded 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: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.027 m/yr | 7 |
| Phosphorus | ↑ Improving | -0.47 µg/L/yr | 7 |
County Ranking
Ranked #4 of 11 lakes in Langlade County
Nearby Lakes in Langlade County
Frequently asked questions about Mary Lake
Where is Mary Lake?
- Mary Lake is a lake in Langlade County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Mary Lake?
- Mary Lake in Langlade County, Wisconsin has a water quality grade of B (Good). Water clarity: 7 ft visibility. Phosphorus: 18.3 µg/L. Maximum depth: 20 ft. Surface area: 154 acres.
Is Mary Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Mary Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is Mary Lake?
- Mary Lake has a maximum depth of 20 feet. The lake covers 154 acres.
What fish are in Mary Lake?
- Fish species found in Mary Lake include Panfish, Largemouth Bass. Mary Lake is located in Langlade County, Wisconsin.
What did the DNR fisheries survey find at Mary Lake?
- Wisconsin DNR lists Largemouth Bass as common on Mary Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Mary Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 7 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Mary Lake?
- Mary Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Mary Lake. Public access is listed as yes.
Explore Mary Lake across LakeQuality
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Moderate nutrients, good water quality
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State Parks Near Mary Lake
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
Where this data comes from
42 measurements from 2 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX42 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (2)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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