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LakeQuality

Shields Lake

NR
Not yet rated
2.5 ft clear · Eutrophic · 940 acres
Limited DataEutrophic

Shields Lake in Rice County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 2.5 ft visibility. Maximum depth: 42 ft. Surface area: 940.49 acres.

Clarity
2.5 ft
Max depth
42 ft
Area
940 acres
Trend
Improving
Public access
Yes
Ice-out
Apr 5
Open water
240 days

Next lake in Rice County

FHunt Lake3 ft clear · Rice CountyView →
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Free interactive depth-contour map of Shields Lake, reaching a maximum surveyed depth of 30 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.

Why Shields 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 Shields 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.

Shields Lake is a 940-acre lake in Rice County, Minnesota with a maximum depth of 42 feet. Overall water quality is improving over recent sampling years. The lake supports 17 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 2 public boat landings.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-08-31. 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

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Water quality measurements for Shields Lake

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

Very murky, less than 2.5 ft of visibility. Trophic State Index: 64.

MetricValueGrade
Water Clarity (Secchi Depth)2.5 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)64Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Shields Lake

Compare lakeside cabins, hotels, and vacation rentals near Shields Lake in Rice 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 Shields 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 →

Lake Details

CharacteristicValue
Maximum Depth42 ft
Surface Area940 acres
Shoreline Length9 mi
Littoral Zone70%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
19 sq mi
Elevation
1,060 ft

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

Recreation & Access

2
Boat Landings
Yes
Public Access
  • Shields LakePublic
  • McCullough County Park CampgroundPublic

Fish Species

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

Fishing Shields 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

13 surveys on file from MN DNR Fisheries. Most recent: 2023-09-13 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Yellow Perch24.840.15 lb
White Crappie22.750.18 lb
Black Crappie21.550.24 lb
Black Bullhead20.740.77 lb
Freshwater Drum16.031.18 lb
Bluegill12.000.27 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.

Yellow Perch

31 fish · 410 in · 2023-07-17
95045678910

Black Crappie

119 fish · 412 in · 2023-07-17
42210trophy 10456789101112

Black Bullhead

111 fish · 815 in · 2023-07-17
3719089101112131415

Freshwater Drum

141 fish · 1122 in · 2023-07-17
39200111213141516171819202122

From the 2023-09-13 survey

Minnesota DNR Fisheries IBI program staff delineated the floating leaf and emergent aquatic vegetation of Shields lake 09/13/2023, following the protocols listed in the MN DNR Lake Plant Mapping Manual. There were a total of 75.3 acres of floating and emergent plants mapped. This consisted of 18.5 acres of emergent…

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 Shields Lake. 3 reports on file.

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

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.031 m/yr5
See year-by-year chart →

Ice Season

Historical ice data from Minnesota DNR (148 observations).

Typical Ice-Out
Apr 5
Typical Ice-In
Dec 1

Estimated open water season: 240 days

EarliestLatest
Ice-Out2024-03-01 (2024)2018-04-30 (2018)
Ice-In2018-11-14 (2018)2004-12-19 (2004)

Most recent ice-out: 2026-03-26

EPA Impairment Status

Shields 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 MN66-0055-00 · Official waterbody report

Graded lakes near Shields Lake

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

Nearby Lakes in Rice County

Frequently asked questions about Shields Lake

What is the water quality grade for Shields Lake?

Shields Lake in Rice County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 2.5 ft visibility. Maximum depth: 42 ft. Surface area: 940.49 acres.

Is Shields Lake safe to swim in?

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

Shields Lake has a maximum depth of 42 feet. The lake covers 940.49 acres.

What fish are in Shields Lake?

Fish species found in Shields Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, freshwater drum, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white bass, yellow bullhead, yellow perch. Shields Lake is located in Rice County, Minnesota.

When does Shields Lake thaw?

Shields Lake typically has ice-out around Apr 5. Ice typically forms around Dec 1. The open water season is approximately 240 days.

Are there boat ramps on Shields Lake?

Shields Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Shields Lake, McCullough County Park Campground. Public access is listed as yes.

Where this data comes from

52 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 WaterMNPCA52 samples · 2020–2025

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

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