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LakeQuality

Lady Slipper Lake

NR
Not yet rated
1 ft clear · Hypereutrophic · 286 acres
Limited DataHypereutrophic

Lady Slipper Lake in Lyon County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 1 ft visibility. Maximum depth: 11 ft. Surface area: 286.15 acres.

Clarity
1 ft
Max depth
11 ft
Area
286 acres
Trend
Improving
Public access
Yes

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FCottonwood Lake1.8 ft clear · Lyon CountyView →
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Why Lady Slipper 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 Lady Slipper 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.

Lady Slipper Lake is a 286-acre lake in Lyon County, Minnesota with a maximum depth of 11 feet. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including black bullhead, common carp, and hybrid sunfish. Public access is available with 1 public boat landing.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-04. Grade methodology: LakeGrade methodology.

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Swimming Safety

Not rated

Limited data

Not rated for swimming — there is not enough monitoring data to judge this lake

Compare the safest swimming lakes near Willmar

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Water quality measurements for Lady Slipper Lake

These readings exist but do not meet the evidence bar for an A–F grade — see why.

Very murky, less than 1 ft of visibility. Trophic State Index: 77.

MetricValueGrade
Water Clarity (Secchi Depth)1 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)77Hypereutrophic

Very high nutrients, dense algae, poor clarity

Where to stay near Lady Slipper Lake

Compare lakeside cabins, hotels, and vacation rentals near Lady Slipper Lake in Lyon 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 Lady Slipper Lake

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Lake Details

CharacteristicValue
Maximum Depth11 ft
Surface Area286 acres
Shoreline Length4.2 mi
Littoral Zone100%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
6 sq mi
Elevation
1,056 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Lady Slipper LakePublic

Fish Species

Click a species to see every graded lake where it is documented.

Fishing Lady Slipper Lake

DNR Fisheries Survey Summary

12 surveys on file from MN DNR Fisheries. Most recent: 2023-09-11 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Bullhead128.270.17 lb
Walleye85.391.15 lb
Common Carp21.803.11 lb
Yellow Perch21.420.22 lb
OSS7.280.04 lb
Bluegill2.960.4 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.

Black Bullhead

395 fish · 39 in · 2022-06-15
21610803456789

Walleye

11 fish · 410 in · 2023-09-11
42045678910

Common Carp

373 fish · 1131 in · 2022-06-15
8241012141618202224262830

Yellow Perch

12 fish · 710 in · 2022-06-15
42078910

From the 2023-09-11 survey

A targeted fall night electrofishing survey was conducted on Lady Slipper during September 11, 2023 to evaluate young of year "YOY" (fingerling sized) Walleye numbers due to a fry stocking. Three electrofishing stations were sampled for a total of 30 minutes. Clarity was poor (1.5 feet). The water temperature was 71…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Lady Slipper Lake. 3 reports on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

Based on 3 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.012 m/yr3

EPA Impairment Status

Lady Slipper Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

MercuryNutrients (phosphorus, nitrogen)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN42-0020-00 · Official waterbody report

Graded lakes near Lady Slipper Lake

Lady Slipper Lake has no grade, but these lakes within a short drive do.

Nearby Lakes in Lyon County

Frequently asked questions about Lady Slipper Lake

What is the water quality grade for Lady Slipper Lake?

Lady Slipper Lake in Lyon County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 1 ft visibility. Maximum depth: 11 ft. Surface area: 286.15 acres.

Is Lady Slipper Lake safe to swim in?

Not rated for swimming — there is not enough monitoring data to judge this lake. Lady Slipper 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 Lady Slipper Lake?

Lady Slipper Lake has a maximum depth of 11 feet. The lake covers 286.15 acres.

What fish are in Lady Slipper Lake?

Fish species found in Lady Slipper Lake include black bullhead, common carp, hybrid sunfish, orangespotted sunfish, walleye, yellow perch. Lady Slipper Lake is located in Lyon County, Minnesota.

Are there boat ramps on Lady Slipper Lake?

Lady Slipper Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lady Slipper Lake. Public access is listed as yes.

Hypereutrophic Lakes in Minnesota

Where this data comes from

17 measurements from 2 monitoring stations, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA17 samples · 2021–2025

Analytical methods

  • Field measurement/observation, generic method
Monitoring station identifiers (2)

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

Named boat-access points from the USGS National Boat Ramps inventory