Long Lake
Hennepin County, Minnesota285 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Long Lake. Here is what has been measured.
- Eutrophic
- Impaired · Impaired biota (cause unknown)
- Eurasian watermilfoil
- 33 ft max depth
- Public access
Long Lake in Hennepin County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.3 ft visibility. Phosphorus: 62 µg/L. Chlorophyll-a (algae): 32 µg/L. Maximum depth: 33 ft. Surface area: 284.99 acres.
Minnesota DNR's Standard Survey on June 26, 2023 caught 4.00 walleye per gill net at Long Lake. Length samples in the latest survey that recorded them ran 13–25 inches. DNR survey details →
Long Lake is a 285-acre productive, nutrient-rich eutrophic lake in Hennepin County, Minnesota with a maximum depth of 33 feet. Overall water quality is declining over recent sampling years. The lake supports 14 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 80 other monitored lakes in Hennepin County, Long Lake ranks #58 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-13. Methodology: how these readings are compared.
Long Lake covers about 280 acres in Hennepin County. It has one public boat landing. The median ice-out date is March 31, which is when the open-water season begins. If you are planning to stay, you can search lake houses and cabins around Long Lake on Vrbo, or look for a hotel room near the lake on Booking.com or Expedia.
What Long Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing14 species recorded
- Ice seasonIce-out around Mar 31
- Deep water33 ft surveyed max depth
Swimming conditions
Readings onlyRecreation use not supported
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. Long Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Long 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 Lake
These are the measurements Minnesota PCA publishes for Long Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 3.3 ft of visibility. Phosphorus 62 µg/L. Chlorophyll-a 32 µg/L. TSI 63.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 62µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 32µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 63 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Long Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Long Lake typically sits around 58°F at the surface in October. Summer average is about 65°F. Usually warmest in Aug (about 67°F) and coldest in Nov (about 46°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (46°F) to its warmest (67°F).
Typical surface water temperature by month, from 860 field readings (2010–2025) via the EPA Water Quality Portal. See the full Long Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Long Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (654,636 cells/mL) on July 18, 2026.
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 June 26, 2023 caught 4.00 walleye per gill net at Long Lake. Length samples in the latest survey that recorded them ran 13–25 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Long 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
10 surveys on file from MN DNR Fisheries. Most recent: 2023-06-26 (Standard Survey).
10 surveys on file · most recent 2023-06-26 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 34.08 | 2–9 in 2023-06-26 | 0.19 lb |
| Black Crappie | 16.69 | 3–10 in 2023-06-26 | 0.21 lb |
| Black Bullhead | 13.21 | 8–13 in 2023-06-26 | 0.58 lb |
| Largemouth Bass | 9.51 | 8–20 in 2023-06-26 | 1.23 lb |
| Yellow Perch | 7.11 | 6–8 in 2023-06-26 | 0.13 lb |
| Walleye | 2.83 | 13–25 in 2023-06-26 | 1.95 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
Black Crappie
Black Bullhead
Largemouth Bass
From the 2023-06-26 survey
Long Lake is a 285-acre lake with a maximum depth of 33 feet. The lake is located within the town of Long Lake, in central Hennepin County. Long is actively managed for Walleye and Northern Pike, with secondary emphasis on Largemouth Bass and Bluegill. Long also supports catchable populations of Black Crappie. The…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Long Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — LongFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — LongFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — LongPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
33 ft
Surface area
285 acres
Shoreline
3.9 mi
Littoral zone
46%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
4 sq mi
HydroLAKES / HydroSHEDS
Elevation
935 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Nelson Lakeside ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Long Lake
Compare lakeside cabins, hotels, and vacation rentals near Long Lake in Hennepin 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Long Lake are listed below.
Top-rated places to stay near Long 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 →
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Fish Species
Click a species to see every lake where it is documented.
Fishing Long 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+6.93 µg/L/yr6 years
Chlorophyll-a
Worsening+2.96 µg/L/yr6 years
Ice season
Typical ice-out
Mar 31
Earliest Mar 3, 2024 · Latest May 2, 2018
Typical ice-in
Dec 3
Earliest Nov 22, 2022 · Latest Dec 19, 2015
Most recent ice-out
Mar 31
2026
31 observations · Minnesota PCA ice records
EPA Impairment Status
Long 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, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN27-0160-00 · Official waterbody report
Nearby Lakes in Hennepin County
Frequently asked questions about Long Lake
Where is Long Lake?
- Long Lake is a lake in Hennepin 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 Lake?
- Long Lake in Hennepin County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.3 ft visibility. Phosphorus: 62 µg/L. Chlorophyll-a (algae): 32 µg/L. Maximum depth: 33 ft. Surface area: 284.99 acres.
Is Long Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Long Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Long Lake?
- Long Lake typically sits around 58°F at the surface in October, from 860 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Long Lake?
- Long Lake has a maximum depth of 33 feet. The lake covers 284.99 acres.
What fish are in Long Lake?
- Fish species found in Long Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, yellow bullhead, yellow perch. Long Lake is located in Hennepin County, Minnesota.
What did the DNR fisheries survey find at Long Lake?
- Minnesota DNR's Standard Survey on June 26, 2023 caught 4.00 walleye per gill net at Long Lake. Length samples in the latest survey that recorded them ran 13–25 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Long 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 Long Lake thaw?
- Long Lake typically has ice-out around Mar 31. Ice typically forms around Dec 3. The open water season is approximately 247 days.
Does Long Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Long Lake (clouds, ice, or an off-season gap). The most recent reading was high (654,636 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Long Lake?
- Long Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Nelson Lakeside Park. Public access is listed as yes.
Can I fish at Long Lake?
- Long 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 Long Lake across LakeQuality
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Where this data comes from
207 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA207 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 (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
Impairment status from EPA ATTAINS 303(d) database
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