Polly Lake
Lake County, Minnesota485 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Polly Lake. Here is what has been measured.
- Impaired · Mercury
- 21 ft max depth
- Limited data
Polly Lake in Lake County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4.5 ft visibility. Maximum depth: 21 ft. Surface area: 485.24 acres.
Minnesota DNR's Standard Survey on September 12, 2016 caught 6.11 walleye per gill net at Polly Lake. Length samples in the latest survey that recorded them ran 7–24 inches. DNR survey details →
Polly Lake is a 485-acre lake in Lake County, Minnesota with a maximum depth of 21 feet (9-foot average). Overall water quality is declining over recent sampling years. The lake supports 8 documented fish species including green sunfish, northern pike, and pumpkinseed. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-08-03. Methodology: how these readings are compared.
What Polly Lake is good for
From access and monitoring records, not editorial picks.
- Fishing8 species recorded
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Polly Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Polly 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 Polly Lake
These are the measurements Minnesota PCA publishes for Polly 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 4.5 ft. TSI 55.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.5ft | 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. | 55 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Polly Lake
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Standard Survey on September 12, 2016 caught 6.11 walleye per gill net at Polly Lake. Length samples in the latest survey that recorded them ran 7–24 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Polly Lake’s water-quality measurements separately, and the water-quality trend over 3 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
3 surveys on file from MN DNR Fisheries. Most recent: 2016-09-12 (Standard Survey).
3 surveys on file · most recent 2016-09-12 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| White Sucker | 10.55 | 7–20 in 2016-09-12 | 1.69 lb |
| Walleye | 7.58 | 7–24 in 2016-09-12 | 0.88 lb |
| Yellow Perch | 3.12 | 2–9 in 2016-09-12 | 0.15 lb |
| Green Sunfish | 1.71 | ||
| Pumpkinseed | 0.93 | 4 in 2002-07-08 | 0.07 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.
White Sucker
Walleye
Yellow Perch
Pumpkinseed
From the 2016-09-12 survey
Polly Lake has an area of 485 acres with a maximum depth of 21 feet and has brown tinted water with clarity around 7 feet. The lake is located within the BWCAW about 23 miles northeast of Isabella, and is a part of a popular canoe route called the Girl Chain. There are three portage routes into the lake. An 85 rod…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Polly Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — PollyFisheries Lake Survey · MN DNR LakeFinder
Lake Details
Max depth
21 ft
Average depth
9 ft
Surface area
485 acres
Shoreline
18.6 mi
Littoral zone
78%
Share shallower than 15 ft
Public access
No
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
39 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,588 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Polly Lake
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Top-rated places to stay near Polly Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Polly Lake
Water quality readings over time
3 seasons of samples on record (2022–2024). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening3 years
EPA Impairment Status
Polly 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: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN38-0104-00 · Official waterbody report
Nearby Lakes in Lake County
Frequently asked questions about Polly Lake
Where is Polly Lake?
- Polly Lake is a lake in Lake County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Polly Lake?
- Polly Lake in Lake County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4.5 ft visibility. Maximum depth: 21 ft. Surface area: 485.24 acres.
Is Polly Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Polly Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
How deep is Polly Lake?
- Polly Lake has a maximum depth of 21 feet and an average depth of 9 feet. The lake covers 485.24 acres.
What fish are in Polly Lake?
- Fish species found in Polly Lake include green sunfish, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow perch. Polly Lake is located in Lake County, Minnesota.
What did the DNR fisheries survey find at Polly Lake?
- Minnesota DNR's Standard Survey on September 12, 2016 caught 6.11 walleye per gill net at Polly Lake. Length samples in the latest survey that recorded them ran 7–24 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Polly Lake’s water-quality measurements separately, and the water-quality trend over 3 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Polly Lake?
- Public access to Polly Lake is listed as no on the lake record, so confirm before you make the trip. 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 Polly Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
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Fish species and best lakes in Lake County
Species activity outlook by water temperature and season
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Where this data comes from
5 measurements from 3 monitoring stations, 2022–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA5 samples · 2022–2024
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (3)
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