Big Lake
Sherburne County, Minnesota254 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Big Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Impaired biota (cause unknown)
- 2 aquatic invasives
- 48 ft max depth
- Public access
Big Lake in Sherburne County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 13.6 ft visibility. Phosphorus: 10.5 µg/L. Chlorophyll-a (algae): 6.1 µg/L. Maximum depth: 48 ft. Surface area: 253.66 acres.
Minnesota DNR's Standard Survey on July 31, 2017 caught 4.50 walleye per gill net at Big Lake. DNR survey details →
Big Lake is a 254-acre mesotrophic lake in Sherburne County, Minnesota with a maximum depth of 48 feet (18-foot average). Overall water quality is declining over recent sampling years. The lake supports 14 documented fish species including black crappie, bluegill, and bowfin (dogfish). Public access is available. Compared to the 17 other monitored lakes in Sherburne County, Big Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-25. Methodology: how these readings are compared.
Big Lake covers about 250 acres in Sherburne County. The median ice-out date is April 7, which is when the open-water season begins. If you are planning to stay, you can search lake houses and cabins around Big Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Big Lake is good for
From access and monitoring records, not editorial picks.
- Clear water13.6 ft of visibility
- Fishing14 species recorded
- Ice seasonIce-out around Apr 7
- Deep water48 ft surveyed max depth
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. Big Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury. Check local advisories before you swim.
Whether Big 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 Big Lake
These are the measurements Minnesota PCA publishes for Big Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 13.6 ft. Phosphorus 10.5 µg/L. Chlorophyll-a 6.1 µg/L. TSI 42.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 13.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 10.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 6.1µg/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. | 42 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Big Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Big Lake typically sits around 67°F at the surface in September. Summer average is about 76°F. Usually warmest in Jul (about 78°F) and coldest in May (about 60°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (60°F) to its warmest (78°F).
Typical surface water temperature by month, from 64 field readings (2011–2025) via the EPA Water Quality Portal. See the full Big Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Big Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (164,437 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 ↗
Minnesota DNR's Standard Survey on July 31, 2017 caught 4.50 walleye per gill net at Big Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
8 surveys on file from MN DNR Fisheries. Most recent: 2017-07-31 (Standard Survey).
8 surveys on file · most recent 2017-07-31 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluntnose Minnow | 42.28 | ||
| Bluegill | 18.59 | 2–8 in 2017-07-31 | 0.13 lb |
| Largemouth Bass | 13.51 | 4–18 in 2017-07-31 | 0.65 lb |
| Green Sunfish | 11.19 | 4 in 2017-07-31 | 0.07 lb |
| Black Bullhead | 9.17 | 7–12 in 2004-08-02 | 0.77 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.
Bluegill
Largemouth Bass
Green Sunfish
Black Bullhead
From the 2017-07-31 survey
Big Lake is a 251 acre lake located in Sherburne County within the city limits of Big Lake. It is connected to Mitchell Lake via a navigable channel. Big Lake has a maximum depth of 48 feet and a small watershed primarily composed of development, open water, and row crops. A city owned public access is located at the…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Big Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BigFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — BigFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — BigPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
48 ft
Average depth
17.7 ft
Surface area
254 acres
Shoreline
2.4 mi
Littoral zone
43%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Stays via Stay22
Stays near Big Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Lake in Sherburne 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 Big Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
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Fish Species
Click a species to see every lake where it is documented.
Fishing Big 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: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Worsening+3.5 µg/L/yr2 years
Chlorophyll-a
Worsening+1.7 µg/L/yr2 years
Ice season
Typical ice-out
Apr 7
Earliest Mar 10, 2024 · Latest May 3, 2013
Typical ice-in
Dec 10
Earliest Dec 9, 2006 · Latest Dec 27, 2015
Most recent ice-out
Mar 10
2024
23 observations · Minnesota PCA ice records
EPA Impairment Status
Big Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN71-0082-00 · Official waterbody report
Nearby Lakes in Sherburne County
Frequently asked questions about Big Lake
Where is Big Lake?
- Big Lake is a lake in Sherburne County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Big Lake?
- Big Lake in Sherburne County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 13.6 ft visibility. Phosphorus: 10.5 µg/L. Chlorophyll-a (algae): 6.1 µg/L. Maximum depth: 48 ft. Surface area: 253.66 acres.
Is Big Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Big Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury. Check local advisories before you swim.
What is the water temperature of Big Lake?
- Big Lake typically sits around 67°F at the surface in September, from 64 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Big Lake?
- Big Lake has a maximum depth of 48 feet and an average depth of 17.7 feet. The lake covers 253.66 acres.
What fish are in Big Lake?
- Fish species found in Big Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow bullhead, yellow perch. Big Lake is located in Sherburne County, Minnesota.
What did the DNR fisheries survey find at Big Lake?
- Minnesota DNR's Standard Survey on July 31, 2017 caught 4.50 walleye per gill net at Big Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
When does Big Lake thaw?
- Big Lake typically has ice-out around Apr 7. Ice typically forms around Dec 10. The open water season is approximately 247 days.
Does Big Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Big Lake (clouds, ice, or an off-season gap). The most recent reading was high (164,437 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Can I fish at Big Lake?
- Public access to Big 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 Big Lake across LakeQuality
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Sherburne County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Minnesota's cleanest lakes, ranked on agency measurements
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State Parks Near Big Lake
Other Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
109 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
MNPCA109 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 details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate