Clay Lake is a lake in Bayfield County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.

How deep is Clay Lake?

Clay Lake has a maximum depth of 45 feet. The lake covers 28 acres.

What fish are in Clay Lake?

Fish species found in Clay Lake include Panfish, Largemouth Bass. Clay Lake is located in Bayfield County, Wisconsin.

Can I fish at Clay Lake?

Public access to Clay Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.

Clay Lake

Bayfield County, Wisconsin28 acresView map Directions

Wisconsin DNR publishes the water-quality measurements for Clay Lake. Here is what has been measured.

Clarity

3.5 ft

Murkier than most

Secchi · sampled 2023

Max depth

45 ft

Bathymetric survey

Area

28 acres

Surface area

45 ft max depth
Public access
Limited data

See the measurements Directions Where to stay

Clay Lake in Bayfield County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 3.5 ft visibility. Maximum depth: 45 ft. Surface area: 28 acres.

Wisconsin DNR lists Panfish as common on Clay Lake. DNR survey details →

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Clay Lake is a 28-acre lake in Bayfield County, Wisconsin with a maximum depth of 45 feet. Water clarity is improving over recent sampling years. The lake supports 2 documented fish species including Panfish and Largemouth Bass. Public access is available.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2023-08-21. Methodology: how these readings are compared.

What Clay Lake is good for

From access and monitoring records, not editorial picks.

Deep water45 ft surveyed max depth

Swimming conditions

No reading

Limited data

Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

Whether Clay Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

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Water quality measurements for Clay Lake

These are the measurements Wisconsin DNR publishes for Clay Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.

Murky, only visible to about 3.5 ft. TSI 59.

Water quality readings
Measure	Reading	Where it sits
Water clarity (Secchi depth)	3.5ft	Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer.
Total phosphorus		No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.
Chlorophyll-a (algae)		No reading The green pigment in algae — a direct measure of how much algae is in the water.
Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a.	59	Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic

High nutrients, frequent algae, reduced clarity

Ask about Clay Lake

Answers come straight from the public measurements and survey records on this page.

DNR fisheries survey

Wisconsin DNR lists Panfish as common on Clay Lake.

A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Clay Lake’s water-quality measurements separately, and the water-quality trend over 4 years of monitoring is stable. 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.

Fish Species (DNR-rated)

Panfish(Common)Largemouth Bass(Present)

Contour map (PDF) →Full WI DNR LakePage →Water quality stations →

Lake Details

Max depth

45 ft

Surface area

28 acres

Public access

Yes

Listed by Wisconsin DNR

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Stays near Clay Lake

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Fish Species

Panfish Largemouth Bass

Click a species to see every lake where it is documented.

Fishing Clay Lake

Water quality readings over time

3 seasons of samples on record (2020–2023). Calling a direction takes at least 4 years of the same measurement.

Water clarity
Improving
3 years
Phosphorus
Worsening
+0.5 µg/L/yr2 years

Nearby Lakes in Bayfield County

Perch Lake—View →Wishbone Lake4.8 ft clear—View →Reynard Lake10.2 ft clear—View →Stratton Ponds9.8 ft clear—View →Bufo Lake10 ft clear—View →Armstrong Lake—View →

Frequently asked questions about Clay Lake

Where is Clay Lake?: Clay Lake is a lake in Bayfield County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Clay Lake?: Clay Lake in Bayfield County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 3.5 ft visibility. Maximum depth: 45 ft. Surface area: 28 acres.
Is Clay Lake safe to swim in?: Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Clay Lake?: Clay Lake has a maximum depth of 45 feet. The lake covers 28 acres.
What fish are in Clay Lake?: Fish species found in Clay Lake include Panfish, Largemouth Bass. Clay Lake is located in Bayfield County, Wisconsin.
What did the DNR fisheries survey find at Clay Lake?: Wisconsin DNR lists Panfish as common on Clay Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Clay Lake’s water-quality measurements separately, and the water-quality trend over 4 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Clay Lake?: Public access to Clay Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.

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Where this data comes from

2 measurements from 1 monitoring station, 2021–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

Eastern Regional OfficeUSFSEASTERN2 samples · 2021–2023

Monitoring station identifiers (1)

USFSEASTERN-2758500

EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.