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Boulder Lake
Enhanced dataInteractive depth contours
Boulder LakeOconto 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 50% of the lake. Small gaps between recordings are smoothly connected; larger unrecorded areas follow the lake's depth model calibrated to the DNR-documented 11-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 Boulder Lake.
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Fishing forecast
Best windows for Boulder 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
Boulder Lake water temperature today
Modeled surface-temperature estimate built from seasonal climate, lake depth, and live National Weather Service air temperatures near this lake.
77°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.
DNR water check
Water quality quick take
From Wisconsin DNR / Citizen Lake Monitoring readings at Boulder Lake - Deep Hole.
Sampled May 2026Volunteer monitoring since 2003
Clear, low-algae water — summer clarity of 11.5 ft is clearer than most monitored Wisconsin lakes.
Based on July–August 2022 averages across 4 volunteer readings.42Mesotrophic5-yr summer TSI
Moderately clear with moderate nutrients — a typical profile for good swimming lakes.
Water claritySecchi disk depth
11.5 ftJul–Aug 2022 avg (2 readings)
ClearStable since 2017
Clearer than 64% of 596 monitored Wisconsin lakes with current readings.
AlgaeChlorophyll-a
3 µg/LJul–Aug 2022 avg (2 readings)
LowWorsening — up ~75% vs earlier years
NutrientsTotal phosphorus — fuels plant & algae growth
16 µg/LLatest single sample · 2024-05-29
LowLow phosphorus means light 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 | 11.0 ft (1) | 4.0 µg/L (1) | — |
| 2024 | — | 5.0 µg/L (1) | — |
| 2023 | 11.0 ft (1) | 5.0 µg/L (1) | 16.0 µg/L (1) |
| 2022 | 11.5 ft (2) | 3.0 µg/L (2) | — |
| 2021 | 11.0 ft (2) | 3.0 µg/L (2) | — |
| 2020 | 12.0 ft (1) | 2.0 µg/L (1) | — |
| 2019 | 11.0 ft (2) | 3.5 µg/L (2) | — |
| 2018 | 11.0 ft (1) | 2.0 µg/L (2) | — |
| 2017 | 11.0 ft (2) | 4.0 µg/L (2) | — |
| 2016 | 11.0 ft (1) | 1.0 µg/L (1) | — |
Latest individual samples: Secchi 11 ft (2026-05-31), chlorophyll-a 2 µg/L (2025-09-15), and total phosphorus 16 µg/L (2024-05-29).
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.
Boulder Lake - Deep HoleStation 433081 · 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 sheetFishing 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
Boulder Lake depth maps
1 converted map sheet. These historical surveys are not for navigation.
Navigable depth map
Boulder 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 491800 · 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 2021 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 contextThe 2021 comprehensive survey used 72 fyke-net nights and 3.8 shoreline miles of electrofishing to assess Boulder Lake (WBIC 491800); the source notes the lake also extends into Langlade County, while the exact LakeList target is its Oconto County record.
The 2021 comprehensive survey used 72 fyke-net nights and 3.8 shoreline miles of electrofishing to assess Boulder Lake (WBIC 491800); the source notes the lake also extends into Langlade County, while the exact LakeList target is its Oconto County record.
- Historical fisheries snapshot; not current fishing regulations or navigation guidance.
- Only metrics explicitly supported by the cited source page were promoted.
- Relative-abundance indices, estimates, confidence bounds, gear limitations and size thresholds retain source scope.
Black Crappie
28 fishTotal survey catch · p. 71.8 percentPercent of total survey catch · p. 710.8 inchesAverage length · p. 75.4 inchesMinimum observed length · p. 7
Bluegill
388 fishTotal survey catch · p. 724.8 percentPercent of total survey catch · p. 77.3 inchesAverage length · p. 72.7 inchesMinimum observed length · p. 7
Brook Trout
13 fishTotal survey catch · p. 70.8 percentPercent of total survey catch · p. 79 inchesAverage length · p. 78 inchesMinimum observed length · p. 7
Brown Trout
15 fishTotal survey catch · p. 71 percentPercent of total survey catch · p. 77.9 inchesAverage length · p. 77.2 inchesMinimum observed length · p. 7
Largemouth Bass
255 fishTotal survey catch · p. 716.3 percentPercent of total survey catch · p. 712.4 inchesAverage length · p. 73.6 inchesMinimum observed length · p. 7
Northern Pike
12 fishTotal survey catch · p. 70.8 percentPercent of total survey catch · p. 727.4 inchesAverage length · p. 718.8 inchesMinimum observed length · p. 7
Pumpkinseed
2 fishTotal survey catch · p. 70.1 percentPercent of total survey catch · p. 75 inchesAverage length · p. 74.2 inchesMinimum observed length · p. 7
Rock Bass
596 fishTotal survey catch · p. 738.2 percentPercent of total survey catch · p. 75.8 inchesAverage length · p. 73.4 inchesMinimum observed length · p. 7
Smallmouth Bass
201 fishTotal survey catch · p. 712.9 percentPercent of total survey catch · p. 711.2 inchesAverage length · p. 75.4 inchesMinimum observed length · p. 7
Yellow Perch
47 fishTotal survey catch · p. 73 percentPercent of total survey catch · p. 77.6 inchesAverage length · p. 74.7 inchesMinimum observed length · p. 7
Boulder Lake comprehensive summary report, 2021Matched by exact wbic name county · WBICs 491800 · verified 2026-07-19Wisconsin DNR fisheries survey report; LakeList operator documented permission to leverage this public report with source attribution.
Wisconsin DNR · 2026–2027 season
Lake-specific fishing regulations
Rule text published by the DNR for this waterbody, cached by WBIC and verified 2026-07-12.
All species
Catch and release fishing for largemouth and smallmouth bass is open year round unless otherwise noted. Motor Trolling is allowed with up to 3 hooks, baits, or lures, per angler.
Catfish
Season Dates: Open All Year. No minimum length limit and the daily bag limit is 10.
Cisco and whitefish
Season Dates: Open All Year. No minimum length limit and the daily bag limit is 10.
Lake sturgeon
Season Dates: Closed. No fishing allowed.
Largemouth and smallmouth bass
Season Dates: May 2, 2026 to March 7, 2027. The minimum length limit is 14" and the daily bag limit is 5.
Muskellunge and hybrids
Season Dates: May 2, 2026 to December 31, 2026 on open water. The minimum length limit is 40" and the daily bag limit is 1.
Northern pike
Season Dates: May 2, 2026 to March 7, 2027. No minimum length limit and the daily bag limit is 5.
Paddlefish
Season Dates: Closed. No fishing allowed.
Panfish
Season Dates: Open All Year. No minimum length limit and the daily bag limit is 25.
Rock, yellow, and white bass
Season Dates: Open All Year. No minimum length limit and the daily bag limit is unlimited.
Rough fish
Season Dates: Open All Year. No minimum length limit and the daily bag limit is unlimited.
Shovelnose sturgeon
Season Dates: Closed. No fishing allowed.
Trout and salmon
See Trout regulations layer.
Urban waters gamefish
This waterbody is not considered an urban water, Urban Waters Gamefish regulations do not apply.
Walleye, sauger, and hybrids
Season Dates: May 2, 2026 to March 7, 2027. The minimum length is 15", but walleye, sauger, and hybrids from 20" to 24" may not be kept, and only 1 fish over 24" is allowed. The daily bag limit is 3.
Regulations can change. The official DNR page controls; verify seasons, boundaries, bag limits, and emergency rules before fishing.
370surface acres
11max depth feet
2public access points
45.1493, -88.6360latitude, longitude
Access
Public access points
Boat launchAccess at Campground (off Boulder Campground Ln)45.14175, -88.63475Managed by Wisconsin DNR
DNR verifiedDirections
Boat launchBoulder Lake Campground Boat Ramp45.14149, -88.63911Managed by FEDERALTOWN OF DOTYRamp surface: PavedADA-accessible feature: YesVerified 2026-07-12
Nearby
Trip-planning places
No nearby trip-planning places yet
Fishery
Notable species
Largemouth BassPanfishNorthern PikeSmallmouth BassWalleye
Depth FAQ
How deep is Boulder Lake?
Boulder Lake is 11 feet deep at its deepest point and averages about 7 feet, according to Wisconsin DNR records.
Is there a free depth map of Boulder Lake?
Yes. LakeList publishes a free interactive depth contour map of Boulder 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 Boulder 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 Pagesname, coordinates, county, source identifiers
LakeList record updated 2026-07-12