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Mason Lake
Enhanced dataInteractive depth contours
Mason LakeAdams County, WI
Contours load with map Access
Interactive depth contours5-foot typical interval · Sonar-derived depth (C-MAP Genesis) · Gaps interpolated · Not for navigation
Source: C-MAP Genesis community sonar (derived)high confidence · QA passed · Select a contour to inspect its mapped depthDepths decoded from C-MAP Genesis Social Map community sonar recordings (used with permission), covering 84% of the lake. Small gaps between recordings are smoothly connected; larger unrecorded areas follow the lake's depth model calibrated to the DNR-documented 9-ft maximum depth. More accurate than a pure model, but still an estimate. Not for navigation.LakeList assistant
Plan your lake day
Fishing spots, food, lodging, marinas, and rentals around Mason Lake.
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Fishing forecast
Best windows for Mason Lake
Weather-based planning built from the National Weather Service hourly forecast near this lake.
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Checking wind, precipitation, and near-term weather windows.
Water temperature
Mason Lake water temperature today
Modeled surface-temperature estimate built from seasonal climate, lake depth, and live National Weather Service air temperatures near this lake.
78°FPeak summer
Seasonal estimate. Checking current National Weather Service air temperatures…
Warmest water of the year. Fish hold deeper or feed in low light; swimming and watersports are at their best.
Estimates are modeled, not measured. Actual temperatures vary with depth, wind mixing, and recent weather — verify conditions before swimming, boating, or heading onto ice.
Wisconsin DNR water assessment
Impaired waterbody listed
The DNR lists this waterbody as impaired. This notice is not itself a closure; review the official assessment and current guidance before your trip.
303(d) / impairment recordRecreation restrictions noted
Excess Algal Growth, Elevated pH , EutrophicationPollutants: Total Phosphorus
- Status
- TMDL Approved
- Public health
- General Advice
- Recreation
- Recreational Restrictions
- Aquatic life
- Not specified
Water is impaired due to one or more pollutants and associated quality impacts.
Review DNR water quality Check consumption advice Source updated 2026-03-25 · LakeList verified 2026-07-12
DNR water check
Water quality quick take
From Wisconsin DNR / Citizen Lake Monitoring readings at Mason Lake - Deep Hole.
Sampled Jun 2026Volunteer monitoring since 1993
Murky, algae-prone water — summer clarity of 1.3 ft ranks among the lowest of monitored Wisconsin lakes.
Based on July–August volunteer averages from 2024–2025; each value shows its own year.73Hypereutrophic5-yr summer TSI
Very nutrient-rich water — heavy algae and plant growth pressure.
Water claritySecchi disk depth
1.3 ftJul–Aug 2024 avg (4 readings)
MurkyStable since 2018
Clearer than 2% of 596 monitored Wisconsin lakes with current readings.
AlgaeChlorophyll-a
70 µg/LJul–Aug 2025 avg (2 readings)
HighImproving — down ~31% vs earlier years
NutrientsTotal phosphorus — fuels plant & algae growth
163 µg/LJul–Aug 2025 avg (2 readings)
HighStable since 2018
High phosphorus points to heavy plant/algae growth pressure.
All readings by year · station details · methodology
Summer averages (July/August)
July/August means; counts in parentheses show how many samples went into each average.
| Year | Secchi | Chlorophyll-a | Total phosphorus |
|---|---|---|---|
| 2025 | 1.0 ft (1) | 70.0 µg/L (2) | 163.0 µg/L (2) |
| 2024 | 1.3 ft (4) | 58.7 µg/L (3) | 122.0 µg/L (1) |
| 2023 | 1.4 ft (4) | 70.5 µg/L (4) | 112.0 µg/L (1) |
| 2022 | 1.0 ft (2) | 71.0 µg/L (4) | 110.3 µg/L (3) |
| 2021 | 0.9 ft (2) | 130.0 µg/L (3) | 126.0 µg/L (2) |
| 2020 | 1.3 ft (4) | 86.5 µg/L (2) | 110.0 µg/L (2) |
| 2019 | 1.3 ft (4) | 132.0 µg/L (2) | 166.5 µg/L (2) |
| 2018 | 1.1 ft (4) | 94.0 µg/L (2) | 116.0 µg/L (1) |
| 2017 | 1.5 ft (4) | 44.5 µg/L (4) | — |
| 2016 | 1.2 ft (4) | 84.8 µg/L (4) | 125.3 µg/L (4) |
Latest individual samples: Secchi 2 ft (2026-06-29), chlorophyll-a 36 µg/L (2026-06-29), and total phosphorus 105 µg/L (2026-06-29).
Secchi clarity is how deep a black-and-white disk stays visible from the surface — more feet means clearer water.
Chlorophyll-a is an algae pigment; higher values signal more algae in the water column.
Total phosphorus is a nutrient that feeds algae and aquatic plants. It is not a weed survey — depth, bottom type, water movement, and management change the actual lake experience.
Mason Lake - Deep HoleStation 013029 · TSI based on chlorophyll
Modeled from DNR/CLMN monitoring — not a safety or swim-condition report. Verify current conditions locally. LakeList verified 2026-07-12.Official Wisconsin information
Plan with DNR sources
LakeList links to the authoritative record so you can verify maps, rules, and current notices before leaving.
Historical DNR depth maps1 converted map sheetView DNR depth mapHistorical map · not for navigationFishing regulationsVerify current seasons, limits, and restrictionsOfficial DNR lake pageFacts, advisories, boating, and water qualityWater quality reportsMonitoring stations, clarity, and DNR reportsInvasive speciesVerified, observed, and historical AIS recordsBoating ordinancesLocal slow-no-wake and water-use restrictionsFish consumption advisoriesStatewide and waterbody-specific health guidance
Historical depth maps are not for navigation. Verify regulations and access at the official source before your trip.
Historical Wisconsin DNR maps
Mason Lake depth maps
1 converted map sheet. These historical surveys are not for navigation.
Navigable depth map
Mason Lake · sheet 1
Pan, zoom, and inspect the converted Wisconsin DNR historical map image in the browser. Historical survey — not for navigation.
Source: Wisconsin DNR · WBIC 175700 · image navigation only; spatial alignment pending · Historical lake maps are not for navigation.
Source: Wisconsin Department of Natural Resources. Converted for browser access with source URLs, checksums, and retrieval dates retained. Historical lake maps are not for navigation.
882surface acres
9max depth feet
3public access points
43.6578, -89.6079latitude, longitude
Access
Public access points
Boat launchAccess Nr The End Of 1st Dr And Grouse Ct43.65231, -89.60837Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchAccess Off Golden Dr43.66205, -89.60957Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchLake Mason Access43.65399, -89.58669Managed by Wisconsin DNR
DNR verifiedDirections
Nearby
Trip-planning places
No nearby trip-planning places yet
Fishery
Notable species
Largemouth BassCatfishMuskyNorthern PikePanfish
Depth FAQ
How deep is Mason Lake?
Mason Lake is 9 feet deep at its deepest point and averages about 7 feet, according to Wisconsin DNR records.
Is there a free depth map of Mason Lake?
Yes. LakeList publishes a free interactive depth contour map of Mason Lake at a typical 5-foot interval, with an optional 3D underwater view, derived from C-MAP Genesis community sonar (derived) survey data.
Where does the Mason Lake depth map come from?
The interactive depth contours are derived from C-MAP Genesis community sonar (derived). Each contour set passes a visual QA review against the source document before it is published. The depths are derived from community sonar recordings (C-MAP Genesis Social Map, used with permission), with gaps between recordings interpolated; not for navigation.
Trust and freshness
Where this lake data comes from
Wisconsin DNR Lake Mapsname, coordinates, county, source identifiers
LakeList record updated 2026-07-14
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