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LakeQuality

Eagle Lake

NR
Not yet rated
1 ft clear · Hypereutrophic · 898 acres
Limited DataHypereutrophic

Eagle Lake in Blue Earth County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 1 ft visibility. Maximum depth: 9 ft. Surface area: 898.23 acres.

Clarity
1 ft
Typical in August
79°F
Max depth
9 ft
Area
898 acres
Public access
Yes

Next lake in Blue Earth County

FGeorge Lake2.2 ft clear · Blue Earth CountyView →
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Free interactive depth-contour map of Eagle Lake, reaching a maximum surveyed depth of 10 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.

Why Eagle 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 Eagle 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.

Eagle Lake is a 898-acre lake in Blue Earth County, Minnesota with a maximum depth of 9 feet. Limited fish-species data available. Public access is available with 1 public boat landing.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-09-19. 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 Mankato

Get alerts for Eagle Lake

Water quality measurements for Eagle 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 Eagle Lake

Compare lakeside cabins, hotels, and vacation rentals near Eagle Lake in Blue Earth 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 Eagle Lake

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 →

Water Temperature

Eagle Lake typically sits around 79°F at the surface in August. Summer average is about 78°F. Usually warmest in Jul (about 81°F) and coldest in Sep (about 67°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
71°
Jun
74°
Jul
81°
Aug
79°
Sep
67°
Oct
Nov
Dec

Typical surface water temperature by month, from 31 field readings (20112023) via the EPA Water Quality Portal. See the full Eagle Lake water temperature breakdown →

Blue-Green Algae (Cyanobacteria)

No current satellite reading

There’s no recent EPA CyAN cyanobacteria estimate for Eagle Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was very high (1,584,893 cells/mL) on July 19, 2026.

Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗

Lake Details

CharacteristicValue
Maximum Depth9 ft
Surface Area898 acres
Shoreline Length9.8 mi
Littoral Zone80%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
14 sq mi
Elevation
978 ft

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

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Eagle LakePublic

Fishing Eagle 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.

Eurasian watermilfoil

DNR Fisheries Survey Summary

4 surveys on file from MN DNR Fisheries. Most recent: 2023-04-19 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Bullhead273.880.11 lb
Black Crappie5.250.26 lb
Walleye4.601.36 lb
Common Carp3.892.71 lb
Northern Pike3.543.35 lb
Freshwater Drum2.401.1 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

2,011 fish · 413 in · 2004-06-14
1103552045678910111213

Black Crappie

167 fish · 210 in · 2004-06-14
97490trophy 102345678910

Walleye

58 fish · 1026 in · 2004-06-14
950trophy 24101214161820222426

Common Carp

99 fish · 1130 in · 2004-06-14
3417012141618202224262830

From the 2023-04-19 survey

Two trap nets were set on 19 April 2023 to assess winterkill. Trap nets were set on the north shore, near the inlet which is an area fish have traditionally congregated. Black Bullhead was the only species sampled. Dead Walleye and Common Carp were observed along the shoreline.

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 Eagle Lake. 3 reports on file.

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

EPA Impairment Status

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

Causes of impairment

Nutrients (phosphorus, nitrogen)

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

Source: EPA ATTAINS assessment unit MN07-0060-01 · Official waterbody report · Matched by proximity (1.05 km)

Regulated Pollution Sources Nearby

1 EPA-permitted facility operate within about 5 miles of Eagle Lake under Clean Water Act (NPDES) discharge permits.

  • Hiniker Co
    Mankato · 2.7 mi away · NPDES MN0064408

Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.

Graded lakes near Eagle Lake

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

Nearby Lakes in Blue Earth County

Frequently asked questions about Eagle Lake

What is the water quality grade for Eagle Lake?

Eagle Lake in Blue Earth County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 1 ft visibility. Maximum depth: 9 ft. Surface area: 898.23 acres.

Is Eagle Lake safe to swim in?

Not rated for swimming — there is not enough monitoring data to judge this lake. Eagle Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.

What is the water temperature of Eagle Lake?

Eagle Lake typically sits around 79°F at the surface in August, from 31 EPA Water Quality Portal field readings (2011–2023). That is a typical value for the month, not a live reading.

How deep is Eagle Lake?

Eagle Lake has a maximum depth of 9 feet. The lake covers 898.23 acres.

Does Eagle Lake have blue-green algae?

There is no recent EPA CyAN cyanobacteria estimate for Eagle Lake (clouds, ice, or an off-season gap). The most recent reading was very high (1,584,893 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.

Are there boat ramps on Eagle Lake?

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

Hypereutrophic Lakes in Minnesota

Where this data comes from

10 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA10 samples · 2023

Analytical methods

  • Field measurement/observation, generic method
Monitoring station identifiers (1)

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

Regulated discharger data from EPA ECHO (ICIS-NPDES)

Lake size & watershed from HydroLAKES (HydroSHEDS)

Lake details from Minnesota DNR LakeFinder

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