Round Lake
Anoka County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for Round Lake. Here is what has been measured.
- Mesotrophic
- 34 ft max depth
- Public access
Round Lake in Anoka County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 8.9 ft visibility. Phosphorus: 19 µg/L. Chlorophyll-a (algae): 5.3 µg/L.
Round Lake is a mesotrophic lake in Anoka County, Minnesota with an estimated average depth of about 34 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 22 other monitored lakes in Anoka County, Round Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-24. Methodology: how these readings are compared.
What Round Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Ice seasonIce-out around Mar 22
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 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.
Moderate clarity, visible to about 8.9 ft. Phosphorus 19 µg/L. Chlorophyll-a 5.3 µg/L. TSI 46.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 19µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 5.3µg/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. | 46 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Round Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Round Lake typically sits around 70°F at the surface in September. Summer average is about 75°F. Usually warmest in Jul (about 78°F) and coldest in May (about 67°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (67°F) to its warmest (78°F).
Typical surface water temperature by month, from 56 field readings (2016–2025) via the EPA Water Quality Portal. See the full Round Lake water temperature breakdown →
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 high (510,505 cells/mL) on May 9, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Round Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Public Water Access Sites — RoundPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
~34 ft est.
Public access
Yes
Listed by Minnesota PCA
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Minnesota has not published bathymetry for Round Lake.
Lake Size & Watershed
Watershed (drainage) area
3 sq mi
HydroLAKES / HydroSHEDS
Surface area
272 acres
HydroLAKES / HydroSHEDS
Shoreline
2.8 mi
HydroLAKES / HydroSHEDS
Elevation
850 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- 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 Anoka 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.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
Follow Round Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Round Lake
Water Quality Trend: Improving
Based on 4 years of monitoring (2021–2025).
Water clarity
Improving4 years
Phosphorus
Improving-1 µg/L/yr3 years
Chlorophyll-a
Stable0 µg/L/yr3 years
Ice season
Typical ice-out
Mar 22
Earliest Mar 1, 2024 · Latest Mar 28, 2020
Typical ice-in
Nov 27
Earliest Nov 10, 2018 · Latest Dec 7, 2016
Most recent ice-out
Mar 1
2024
9 observations · Minnesota PCA ice records
Nearby Lakes in Anoka County
Frequently asked questions about Round Lake
Where is Round Lake?
- Round Lake is a lake in Anoka 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 Anoka County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 8.9 ft visibility. Phosphorus: 19 µg/L. Chlorophyll-a (algae): 5.3 µg/L.
Is Round Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Round Lake?
- Round Lake typically sits around 70°F at the surface in September, from 56 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.
How deep is Round Lake?
- No published bathymetric survey covers Round Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 34 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
When does Round Lake thaw?
- Round Lake typically has ice-out around Mar 22. Ice typically forms around Nov 27. The open water season is approximately 250 days.
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 high (510,505 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Round Lake?
- Round Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Round Lake. Public access is listed as yes.
Can I fish at Round Lake?
- Round Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. 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
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Anoka County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Rum River Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
Other Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
132 measurements from 1 monitoring station, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA132 samples · 2021–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity, Nephelometric Method
- Turbidity, Probe Method
Monitoring station identifiers (1)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate