Round Lake
Sawyer County, Wisconsin3,294 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Round Lake. Here is what has been measured.
- Oligotrophic
- 2 aquatic invasives
- 74 ft max depth
- Public access
Round Lake in Sawyer County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 21.1 ft visibility. Phosphorus: 14 µg/L. Chlorophyll-a (algae): 0.9 µg/L. Maximum depth: 74 ft. Surface area: 3294 acres.
Wisconsin DNR rates Largemouth Bass, Smallmouth Bass, and Walleye as abundant on Round Lake. DNR survey details →
Round Lake is a 3,294-acre cold, clear oligotrophic lake in Sawyer County, Wisconsin with a maximum depth of 74 feet. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 3 public boat landings. Compared to the 44 other monitored lakes in Sawyer County, Round Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-07-06. Methodology: how these readings are compared.
What Round Lake is good for
From access and monitoring records, not editorial picks.
- Clear water21.1 ft of visibility
- Boat launch3 documented ramps
- Fishing6 species recorded
- Deep water74 ft surveyed max depth
- Big water3,294 acres
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Round 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.
Water quality measurements for Round Lake
These are the measurements Wisconsin DNR publishes for Round Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 21.1 ft down. Phosphorus 14 µg/L. Chlorophyll-a 0.9 µg/L. TSI 35.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 21.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 14µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 0.9µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 35 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Round Lake
Answers come straight from the public measurements and survey records on this page.
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Round Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (22,491 cells/mL) on November 22, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Wisconsin DNR rates Largemouth Bass, Smallmouth Bass, and Walleye as abundant on Round Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Round Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is improving. 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. Monitored by volunteers since 1995. 11 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Round Lake covering fish populations, stocking, water quality, and management. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2025Round Lake spring survey, 2025Fisheries Survey · WI DNR · 2025 (PDF)
- 2023Round Lake spring shocking and netting survey, 2023Spring Shocking Survey · WI DNR · 2023 (PDF)
Lake Details
Max depth
74 ft
Surface area
3,294 acres
Public access
Yes
Listed by Wisconsin DNR
Recreation & Access
- Round LakePublic
- Round LakePublic
- Round LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Round Lake
Compare lakeside cabins, hotels, and vacation rentals near Round Lake in Sawyer County, Wisconsin — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Round Lake
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Planning a trip? Cabins and lodging at Round Lake → · more Wisconsin lake trips
Follow Round Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Round Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: Improving
Based on 7 years of monitoring (2020–2026).
Water clarity
Improving7 years
Phosphorus
Worsening+1 µg/L/yr6 years
Chlorophyll-a
Improving-0.05 µg/L/yr5 years
Nearby Lakes in Sawyer County
Frequently asked questions about Round Lake
Where is Round Lake?
- Round Lake is a lake in Sawyer County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Round Lake?
- Round Lake in Sawyer County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 21.1 ft visibility. Phosphorus: 14 µg/L. Chlorophyll-a (algae): 0.9 µg/L. Maximum depth: 74 ft. Surface area: 3294 acres.
Is Round Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Round Lake?
- Round Lake has a maximum depth of 74 feet. The lake covers 3294 acres.
What fish are in Round Lake?
- Fish species found in Round Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Round Lake is located in Sawyer County, Wisconsin.
What did the DNR fisheries survey find at Round Lake?
- Wisconsin DNR rates Largemouth Bass, Smallmouth Bass, and Walleye as abundant on Round Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Round Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Does Round Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Round Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (22,491 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Round Lake?
- Round Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Round Lake, Round Lake, Round Lake. Public access is listed as yes.
Can I fish at Round Lake?
- Round Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. 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.
Explore Round Lake across LakeQuality
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Fish species and best lakes in Sawyer County
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Where to stay at Wisconsin's top lakes, each with its readings
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Compare Round Lake With Nearby Lakes
Where this data comes from
320 measurements from 7 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Lac Courte Oreilles (Tribal)
LCOWIS_WQX221 samples · 2020–2024 - Wisconsin Department of Natural Resources
WIDNR_WQX99 samples · 2020–2026
Analytical methods
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 4500 P F ~ Phosphorus in Water by Colorimetry Automated Ascorbic Acid Method
- 2320 B ~ Alkalinity by Gran Titration
- 4500 P E ~ Phosphorus by Ascorbic Acid
- 10200 H ~ Chlorophyll a-b-c Determination
- Total Phosphorus After Block Digestion
- Phosphorus by Colorimetry
Monitoring station identifiers (7)
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.
Other records on this page
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory