Brule Lake
Brule Lake in Cook County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 10 ft visibility. Maximum depth: 78 ft. Surface area: 4326.71 acres.
- Clarity
- 10 ft
- Max depth
- 78 ft
- Area
- 4,327 acres
- Public access
- Yes
- Ice-out
- May 5
Next lake in Cook County
Free interactive depth-contour map of Brule Lake, reaching a maximum surveyed depth of 60 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Why Brule Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Brule Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Brule Lake is a 4,327-acre lake in Cook County, Minnesota with a maximum depth of 78 feet (35-foot average). The lake supports 6 documented fish species including cisco species, northern pike, and smallmouth bass. Public access is available.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-08-19. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Brule Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Good clarity, visible to about 10 ft. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Brule Lake
Compare lakeside cabins, hotels, and vacation rentals near Brule 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 Brule Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 78 ft |
| Average Depth | 35 ft |
| Surface Area | 4,327 acres |
| Shoreline Length | 63.1 mi |
| Littoral Zone | 33% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Brule Lake
DNR Fisheries Survey Summary
6 surveys on file from MN DNR Fisheries. Most recent: 2023-08-24 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Tullibee (Cisco) | 9.54 | 0.94 lb |
| CIS | 7.50 | 0.98 lb |
| Yellow Perch | 3.40 | 0.08 lb |
| Walleye | 2.55 | 1.39 lb |
| White Sucker | 2.49 | 3.05 lb |
| Northern Pike | 0.78 | 1.85 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
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.
Tullibee (Cisco)
CIS
Yellow Perch
Walleye
From the 2023-08-24 survey
A temperature-dissolved oxygen profile was collected in the deepest basin on Brule Lake on August 24th, 2023, to evaluate the amount of cold, oxygenated water (i.e., oxythermal habitat) available to Cisco, also known as Tullibee. Based on the profile, the top of the thermocline (i.e., the location in the water column…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Brule Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BruleFisheries Lake Survey · MN DNR LakeFinder
- —Public Water Access Sites — BrulePublic Water Access Sites · MN DNR LakeFinder
Ice Season
Historical ice data from Minnesota DNR (8 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2010-04-12 (2010) | 2008-05-14 (2008) |
Most recent ice-out: 2010-04-12
EPA Impairment Status
Brule Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN16-0348-00 · Official waterbody report
Nearby Lakes in Cook County
Frequently asked questions about Brule Lake
What is the water quality grade for Brule Lake?
- Brule Lake in Cook County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 10 ft visibility. Maximum depth: 78 ft. Surface area: 4326.71 acres.
Is Brule Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Brule Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
How deep is Brule Lake?
- Brule Lake has a maximum depth of 78 feet and an average depth of 35 feet. The lake covers 4326.71 acres.
What fish are in Brule Lake?
- Fish species found in Brule Lake include cisco species, northern pike, smallmouth bass, walleye, white sucker, yellow perch. Brule Lake is located in Cook County, Minnesota.
When does Brule Lake thaw?
- Brule Lake typically has ice-out around May 5.
Explore Brule Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
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Fish species and best lakes in Cook County
Species activity outlook by water temperature and season
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Where this data comes from
3 measurements from 3 monitoring stations, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA3 samples · 2020–2024
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (3)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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
Ice data from Minnesota DNR Climate