Long Lake
Hennepin County, MinnesotaEutrophic
Long Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Minnesota average. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Minnesota norms.
A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. Long Lake reaches 33 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. Long Lake covers 285 acres alongside 3.9 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Long Lake ranks 37 of 95 in Hennepin County — solidly in the upper half of the local distribution.
Long Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. The fishery includes walleye alongside the lake's other 14 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been recorded 21 times at Long Lake, with a median around Mar 31. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-27. Grade methodology: LakeGrade methodology.
Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Very murky, less than 3.1 ft of visibility. Phosphorus level: 48 µg/L. Trophic State Index: 61.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.1 ft | F |
| Phosphorus | 48 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 61 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 33 ft |
| Surface Area | 284.99 acres |
| Shoreline Length | 3.9 mi |
| Littoral Zone | 46% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Long Lake (14-day solunar calendar)
→ Is it safe to eat fish from Long Lake? (mercury & PFAS guide)
→ Long Lake fishing regulations (limits, seasons, special rules)
Invasive Species
Water Quality Trend: → Stable
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.024 m/yr | 5 |
| Phosphorus | ↓ Declining | +4.1 µg/L/yr | 5 |
Ice Season
Historical ice data from Minnesota DNR (31 observations).
Estimated open water season: 247 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-03 (2024) | 2018-05-02 (2018) |
| Ice-In | 2022-11-22 (2022) | 2015-12-19 (2015) |
Most recent ice-out: 2026-03-31
Location
County Ranking
Ranked #37 of 95 lakes in Hennepin County
Nearby Lakes in Hennepin County
More Minnesota Lake Rankings
State Parks Near Long Lake
Other Grade D Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Fisheries Survey Summary
10 surveys on file from MN DNR Fisheries. Most recent: 2023-06-26 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 34.08 | 0.19 lb |
| Black Crappie | 16.69 | 0.21 lb |
| Black Bullhead | 13.21 | 0.58 lb |
| Largemouth Bass | 9.51 | 1.23 lb |
| Yellow Perch | 7.11 | 0.13 lb |
| Walleye | 2.83 | 1.95 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.
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.
- —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
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate
Most recent sample: 2024-10-27
Monitoring stations: 1