Round Lake
Cook County, Minnesota154 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Round Lake. Here is what has been measured.
- Oligotrophic
- Impaired · Mercury
- 45 ft max depth
- Public access
- Limited data
Round Lake in Cook County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 16.5 ft visibility. Phosphorus: 8.5 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Maximum depth: 45 ft. Surface area: 154.48 acres.
Minnesota DNR's Standard Survey on July 13, 2015 caught 2.17 walleye per gill net at Round Lake. Length samples in the latest survey that recorded them ran 6–21 inches. DNR survey details →
Round Lake is a 154-acre cold, clear oligotrophic lake in Cook County, Minnesota with a maximum depth of 45 feet. Overall water quality is improving over recent sampling years. The lake supports 5 documented fish species including northern pike, smallmouth bass, and walleye. Public access is available. Compared to the 43 other monitored lakes in Cook County, Round Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-03. Methodology: how these readings are compared.
Round Lake covers about 150 acres in Cook County. Vrbo is where to look for cabins and lake homes around Round Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Round Lake is good for
From access and monitoring records, not editorial picks.
- Clear water16.5 ft of visibility
- Fishing5 species recorded
- Deep water45 ft surveyed max depth
Swimming conditions
Readings onlyLimited data
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. Round Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Round Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR 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 Minnesota PCA 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 16.5 ft down. Phosphorus 8.5 µg/L. Chlorophyll-a 1.6 µg/L. TSI 36.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 16.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 8.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.6µg/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. | 36 | 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.
Water Temperature
Round Lake typically sits around 56°F at the surface in October. Summer average is about 63°F. Usually warmest in Jul (about 66°F) and coldest in May (about 53°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (53°F) to its warmest (66°F).
Typical surface water temperature by month, from 162 field readings (2018–2025) via the EPA Water Quality Portal. See the full Round Lake water temperature breakdown →
Minnesota DNR's Standard Survey on July 13, 2015 caught 2.17 walleye per gill net at Round Lake. Length samples in the latest survey that recorded them ran 6–21 inches.
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 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
10 surveys on file from MN DNR Fisheries. Most recent: 2015-07-13 (Standard Survey).
10 surveys on file · most recent 2015-07-13 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Spottail Shiner | 4.33 | 2 in 2008-07-15 | |
| Walleye | 3.09 | 6–21 in 2015-07-13 | 1.58 lb |
| Yellow Perch | 2.21 | 5–7 in 2015-07-13 | 0.14 lb |
| Smallmouth Bass | 2.13 | 5–16 in 2015-07-13 | 0.67 lb |
| White Sucker | 1.89 | 13–19 in 2015-07-13 | 2.29 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Spottail Shiner
Walleye
Yellow Perch
Smallmouth Bass
From the 2015-07-13 survey
Round Lake is managed primarily for walleye and smallmouth bass. The current (2014) lake management plan established a long range goal for walleye consisting of a minimum gill net catch of 3.0 fish/set, with some fish over 20 inches present. That plan established a size-based long range goal for smallmouth bass: among…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Round Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — RoundFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — RoundFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — RoundPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
45 ft
Surface area
154 acres
Shoreline
2.7 mi
Littoral zone
47%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,739 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Round Lake
Compare lakeside cabins, hotels, and vacation rentals near Round Lake in Cook County, Minnesota — 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
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Fish Species
Click a species to see every lake where it is documented.
Fishing Round Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
EPA Impairment Status
Round Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN16-0606-00 · Official waterbody report
Nearby Lakes in Cook County
Frequently asked questions about Round Lake
Where is Round Lake?
- Round Lake is a lake in Cook County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Round Lake?
- Round Lake in Cook County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 16.5 ft visibility. Phosphorus: 8.5 µg/L. Chlorophyll-a (algae): 1.6 µg/L. Maximum depth: 45 ft. Surface area: 154.48 acres.
Is Round Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Round Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What is the water temperature of Round Lake?
- Round Lake typically sits around 56°F at the surface in October, from 162 EPA Water Quality Portal field readings (2018–2025). That is a typical value for the month, not a live reading.
How deep is Round Lake?
- Round Lake has a maximum depth of 45 feet. The lake covers 154.48 acres.
What fish are in Round Lake?
- Fish species found in Round Lake include northern pike, smallmouth bass, walleye, white sucker, yellow perch. Round Lake is located in Cook County, Minnesota.
What did the DNR fisheries survey find at Round Lake?
- Minnesota DNR's Standard Survey on July 13, 2015 caught 2.17 walleye per gill net at Round Lake. Length samples in the latest survey that recorded them ran 6–21 inches. 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 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Round Lake?
- Public access to Round Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Round Lake across LakeQuality
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Where this data comes from
82 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA82 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder