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Lake Mendota
Enhanced dataInteractive depth contours
Lake MendotaDane County, WI
Contours load with map Access
Interactive depth contours10-foot typical interval · Research survey bathymetry (NTL-LTER) · Not for navigation
Source: North Temperate Lakes LTER surveyhigh confidence · QA passed · Select a contour to inspect its mapped depthSurveyed research bathymetry from the North Temperate Lakes LTER program (University of Wisconsin-Madison, NSF), Yahara Lakes District bathymetry dataset (knb-lter-ntl.153.11, CC-BY). Real measured contours, not a model. Not for navigation.LakeList assistant
Plan your lake day
Fishing spots, food, lodging, marinas, and rentals around Lake Mendota.
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Fishing forecast
Best windows for Lake Mendota
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 Mendota water temperature today
Modeled surface-temperature estimate built from seasonal climate, lake depth, and live National Weather Service air temperatures near this lake.
74°FWarm
Seasonal estimate. Checking current National Weather Service air temperatures…
Comfortable summer pattern. Bass and panfish are active; early and late hours beat the midday heat.
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
High Phosphorus Levels, Excess Algal GrowthPollutants: Total Phosphorus, PCBs
- Status
- TMDL Approved, Pollutant Removed
- 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
Historical volunteer-monitoring record for this lake.
Last sampled Feb 2026Volunteer monitoring 2016–2026
DNR volunteers monitored this lake for about 10 years, ending in 2026. Its final monitored summers showed hazy water (~4.5 ft Secchi) in 2022, elevated algae (chlorophyll ~13 µg/L) in 2022, and high nutrients (phosphorus ~108 µg/L) in 2026.
| Year | Secchi | Chlorophyll-a | Total phosphorus |
|---|---|---|---|
| 2025 | — | — | — |
| 2024 | — | — | — |
| 2023 | — | — | — |
| 2022 | 4.5 ft (2) | 13.0 µg/L (1) | — |
| 2021 | — | — | — |
| 2020 | — | — | — |
Lake Mendota - Central Deep HoleStation 133318
Historical record only — no current water-quality data exists for this lake. 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 maps3 converted map sheetsView 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 Mendota depth maps
3 converted map sheets. These historical surveys are not for navigation.
Navigable depth map
Lake Mendota · 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 805400 · 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.
Wisconsin DNR fisheries survey
Fish population survey
Structured LakeList extraction from the 2024 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 annual fall gill-net monitoring from 2020 through 2024. Every annual metric retains its survey year; no annual catch count is derived from net effort.
DNR documented fluctuating but downward-trending yellow-perch gill-net catch rates, with the lowest value in 2024.
- Only the five explicitly labeled annual CPUE values and two narrative annual mean lengths are promoted.
- Raster length- and age-frequency plots are not converted into unprinted exact values.
- Statewide growth comparators, causal hypotheses and the prior 2014-2019 report are excluded from current metrics.
Yellow perch
61 fish/net-night2020 fall gill-net CPUE · p. 419.8 fish/net-night2021 fall gill-net CPUE · p. 437.1 fish/net-night2022 fall gill-net CPUE · p. 420.4 fish/net-night2023 fall gill-net CPUE · p. 4
Lake Mendota Yellow Perch Summary Report 2020-2024Matched by exact wbic and name county · WBICs 805400 · verified 2026-07-19Wisconsin DNR fisheries survey report; LakeList operator documented permission to leverage this report with source attribution.
9,781surface acres
83max depth feet
12public access points
43.1103, -89.4117latitude, longitude
Access
Public access points
Boat launchGovernor Nelson State Park43.13015, -89.43334Managed by Wisconsin DNR
DNR verifiedDirections
Shore fishingGOVERNOR NELSON STATE PARK FISHING PIER43.13128, -89.43297Managed by Wisconsin DNR verifiedTOWN OF WESTPORTVerified 2026-07-12
Boat launchGovernors Island43.12794, -89.40235Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchMarshall Park Boat Park43.09404, -89.48351Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchMemorial Union43.07695, -89.39896Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchMendota County Park Boat Launch43.10855, -89.47012Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchMiddleton Boat Ramp43.10416, -89.48305Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchOff Univ. Bay Dr.43.08028, -89.42501Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchSpring Harbor43.08108, -89.46983Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchTenney Park Boat Ramp43.09557, -89.36993Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchVeith Avenue Carry-In Access43.13710, -89.40933Managed by STATE(DNR)CITY OF MADISONRamp surface: UnimprovedLanding type: CARRY-INADA-accessible feature: NoVerified 2026-07-12
Boat launchWarner Park Boat Ramp43.12515, -89.37646Managed by CITYCITY OF MADISONRamp surface: ConcreteADA-accessible feature: YesVerified 2026-07-12
Nearby
Trip-planning places
No nearby trip-planning places yet
Fishery
Notable species
PanfishCatfishLargemouth BassNorthern PikeSmallmouth BassWalleyeMuskySturgeon
Depth FAQ
How deep is Lake Mendota?
Lake Mendota is 83 feet deep at its deepest point and averages about 42 feet, according to Wisconsin DNR records.
Is there a free depth map of Lake Mendota?
Yes. LakeList publishes a free interactive depth contour map of Lake Mendota at a typical 10-foot interval, with an optional 3D underwater view, derived from North Temperate Lakes LTER survey survey data.
Where does the Lake Mendota depth map come from?
The interactive depth contours are derived from North Temperate Lakes LTER survey. Each contour set passes a visual QA review against the source document before it is published. The source is measured research bathymetry from the North Temperate Lakes LTER program; 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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