Long Island Lake
Cook County, Minnesota884 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Long Island Lake. Here is what has been measured.
- Impaired · Mercury
- 85 ft max depth
- Limited data
Long Island Lake in Cook County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 9.1 ft visibility. Maximum depth: 85 ft. Surface area: 883.53 acres.
Minnesota DNR's Standard Survey on June 25, 2019 caught 1.25 northern pike per gill net at Long Island Lake. Length samples in the latest survey that recorded them ran 2–27 inches. DNR survey details →
Long Island Lake is a 884-acre lake in Cook County, Minnesota with a maximum depth of 85 feet. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including burbot, lake trout, and northern pike. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-08-13. Methodology: how these readings are compared.
What Long Island Lake is good for
From access and monitoring records, not editorial picks.
- Fishing6 species recorded
- Deep water85 ft surveyed max depth
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Long Island Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Long Island 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 Long Island Lake
These are the measurements Minnesota PCA publishes for Long Island 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 9.1 ft. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9.1ft | 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. | 45 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Long Island Lake
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Standard Survey on June 25, 2019 caught 1.25 northern pike per gill net at Long Island Lake. Length samples in the latest survey that recorded them ran 2–27 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Long Island Lake’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
4 surveys on file from MN DNR Fisheries. Most recent: 2025-08-05 (Targeted Survey).
4 surveys on file · most recent 2025-08-05 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluntnose Minnow | 101.17 | ||
| White Sucker | 3.73 | 6–21 in 2019-06-25 | 1.45 lb |
| Yellow Perch | 1.78 | 2–8 in 2019-06-25 | 0.11 lb |
| Northern Pike | 1.27 | 2–27 in 2019-06-25 | 3 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
Yellow Perch
Northern Pike
From the 2025-08-05 survey
Temperature and dissolved oxygen (DO) measurements were collected from the deepest basin in Long Island Lake on August 5th, 2025, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Trout, the most sensitive coldwater species present in this lake. During the…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Long Island Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Long IslandFisheries Lake Survey · MN DNR LakeFinder
Lake Details
Max depth
85 ft
Surface area
884 acres
Shoreline
23.4 mi
Littoral zone
35%
Share shallower than 15 ft
Public access
No
Listed by Minnesota PCA
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Stays near Long Island Lake
Compare lakeside cabins, hotels, and vacation rentals near Long Island 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 Long Island Lake
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Follow Long Island Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Long Island Lake
- → Long Island Lake fishing: DNR survey catch rates, species & stocking
- → Long Island Lake fishing forecast & best times (species outlook + 14-day solunar calendar)
- → Long Island Lake fishing regulations (limits, seasons, special rules)
- → Is it safe to eat fish from Long Island Lake? (mercury & PFAS guide)
Water quality readings over time
2 seasons of samples on record (2024–2025). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
EPA Impairment Status
Long Island 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.
Source: EPA ATTAINS assessment unit MN16-0460-00 · Official waterbody report
Nearby Lakes in Cook County
Frequently asked questions about Long Island Lake
Where is Long Island Lake?
- Long Island 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 Long Island Lake?
- Long Island Lake in Cook County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 9.1 ft visibility. Maximum depth: 85 ft. Surface area: 883.53 acres.
Is Long Island Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Long Island Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
How deep is Long Island Lake?
- Long Island Lake has a maximum depth of 85 feet. The lake covers 883.53 acres.
What fish are in Long Island Lake?
- Fish species found in Long Island Lake include burbot, lake trout, northern pike, smallmouth bass, white sucker, yellow perch. Long Island Lake is located in Cook County, Minnesota.
What did the DNR fisheries survey find at Long Island Lake?
- Minnesota DNR's Standard Survey on June 25, 2019 caught 1.25 northern pike per gill net at Long Island Lake. Length samples in the latest survey that recorded them ran 2–27 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Long Island Lake’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Long Island Lake?
- Public access to Long Island 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 Long Island Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Cook County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Lake Superior Basin (MN+WI), ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
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State Parks Near Long Island Lake
Other Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
3 measurements from 3 monitoring stations, 2024–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA3 samples · 2024–2025
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 details from Minnesota DNR LakeFinder