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Lake Tomah
Enhanced dataInteractive depth contours
Lake TomahMonroe County, WI
Contours load with map Access
Interactive depth contours5-foot typical interval · Modeled depth estimate · Not a survey · Not for navigation
Source: LakeList depth modelmedium confidence · QA passed · Select a contour to inspect its mapped depthModeled depth estimate: contours computed from the lake's shoreline shape and its documented 19-ft maximum depth (depth grows with distance from shore, calibrated to the documented mean depth where available). This is a smooth mathematical model, not a survey - real holes, bars, and drop-offs will differ. Community sonar (C-MAP Genesis) overlays where recorded. Not for navigation.LakeList assistant
Plan your lake day
Fishing spots, food, lodging, marinas, and rentals around Lake Tomah.
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Fishing forecast
Best windows for Lake Tomah
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
Lake Tomah water temperature today
Modeled surface-temperature estimate built from seasonal climate, lake depth, and live National Weather Service air temperatures near this lake.
75°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
- 303d Listed
- 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 Lake Tomah - Deep Hole.
Last sampled Sep 2025Volunteer monitoring since 1986
Through 2025, high algae readings and high nutrients in the most recent monitored summers.
Based on July–August 2023 averages across 4 volunteer readings.78Hypereutrophic5-yr summer TSI
Very nutrient-rich water — heavy algae and plant growth pressure.
AlgaeChlorophyll-a
190.5 µg/LJul–Aug 2023 avg (2 readings)
HighWorsening — up ~123% vs earlier years
NutrientsTotal phosphorus — fuels plant & algae growth
219.5 µg/LJul–Aug 2023 avg (2 readings)
HighWorsening — up ~66% vs earlier years
High phosphorus points to heavy plant/algae growth pressure.
No recent clarity readings — last measured 2019.
Listed as impaired on the DNR/EPA water-condition assessment — see the notice on this page for details.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 |
|---|---|---|---|
| 2023 | — | 190.5 µg/L (2) | 219.5 µg/L (2) |
| 2022 | — | 131.0 µg/L (2) | 562.5 µg/L (2) |
| 2021 | — | 83.0 µg/L (2) | 152.0 µg/L (2) |
| 2019 | 1.5 ft (2) | 84.5 µg/L (2) | 136.0 µg/L (2) |
| 2018 | 2.6 ft (2) | 59.0 µg/L (2) | 253.5 µg/L (2) |
| 2017 | 1.9 ft (2) | 38.0 µg/L (2) | 171.5 µg/L (2) |
| 2016 | 1.1 ft (2) | 80.0 µg/L (1) | 334.0 µg/L (1) |
| 2015 | 1.6 ft (2) | 66.0 µg/L (2) | 321.5 µg/L (2) |
| 2014 | 1.5 ft (2) | 50.0 µg/L (2) | 418.5 µg/L (2) |
| 2013 | 2.6 ft (2) | 15.0 µg/L (1) | 228.0 µg/L (1) |
Latest individual samples: Secchi 1.3 ft (2019-08-26), chlorophyll-a 109 µg/L (2025-09-01), and total phosphorus 123 µg/L (2023-08-13).
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.
Lake Tomah - Deep HoleStation 423126 · 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
Lake Tomah depth maps
1 converted map sheet. These historical surveys are not for navigation.
Navigable depth map
Lake Tomah · 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 1342100 · 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.
Official fishing intelligence
Fishing reports and forecasts
LakeList matched these official resources by exact lake name and county. Report text stays with the publisher.
Forecasts describe DNR survey findings and expected opportunities; they are not real-time catch reports or a guarantee of fishing conditions.
Wisconsin DNR fisheries survey
Fish population survey
Structured LakeList extraction from the 2025 DNR fisheries survey. Population estimates, density, and catch-rate indices use different units, methods, and scopes, so each value is presented in its original form rather than normalized against a different measure.
Survey indicatorsValues keep their source unit and method; unlike measures are not scaled or compared.
Management contextLake-specific spring fyke-net and night-electrofishing summary; only printed CPUE, size-share and maximum-length values are loaded because raw sample totals are not provided.
DNR characterized high-density panfish, largemouth-bass and northern-pike fisheries, with preferred-size fish and northern pike up to 45 inches.
- The sheet prints rates rather than raw sample totals; no counts are back-calculated.
- Species metrics retain netting or electrofishing gear.
- The report schedules the next survey for 2028.
Black crappie
15 fish/net-nightCaptured per net · p. 18 percentShare at least 10 inches long · p. 1
Bluegill
524 fish/mileCaptured per mile · p. 13 percentShare at least 8 inches long · p. 1
Largemouth bass
73 fish/mileCaptured per mile · p. 233 percentShare at least 15 inches long · p. 2
Northern pike
15 fish/net-nightCaptured per net · p. 236 percentShare at least 28 inches long · p. 245 inchesMaximum captured length · p. 3
Yellow perch
0.3 fish/net-nightCaptured per net · p. 20 percentShare at least 10 inches long · p. 2
2025 Fisheries Information Sheet: Lake Tomah, Monroe CountyMatched by exact wbic and name county · WBICs 1342100 · verified 2026-07-18Wisconsin DNR fisheries survey report; LakeList operator documented permission to leverage this report with source attribution.
245surface acres
19max depth feet
4public access points
43.9815, -90.5247latitude, longitude
Access
Public access points
Boat launchBow Street Boat Ramp43.98464, -90.52458Managed by CITYCITY OF TOMAHRamp surface: Concrete PanelsADA-accessible feature: NoVerified 2026-07-12
Boat launchJuneau St Access43.97580, -90.52000Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchWinnebago Park Boat Ramp43.97963, -90.51938Managed by CITYCITY OF TOMAHRamp surface: ConcreteADA-accessible feature: NoVerified 2026-07-12
Boat launchWinnebago Park - North Boat Ramp43.98067, -90.51860Managed by Wisconsin DNR
DNR verifiedDirections
Nearby
Trip-planning places
No nearby trip-planning places yet
Fishery
Notable species
Largemouth BassNorthern PikePanfish
Depth FAQ
How deep is Lake Tomah?
Lake Tomah is 19 feet deep at its deepest point and averages about 4 feet, according to Wisconsin DNR records.
Is there a free depth map of Lake Tomah?
Yes. LakeList publishes a free interactive depth contour map of Lake Tomah at a typical 5-foot interval, with an optional 3D underwater view, derived from LakeList depth model survey data.
Where does the Lake Tomah depth map come from?
The interactive depth contours are derived from LakeList depth model. Each contour set passes a visual QA review against the source document before it is published. The depths are a modeled estimate calibrated to the lake's documented maximum depth - not a survey, and 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