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LakeQuality

Unnamed Lake

A
Grade A — Excellent
Excellent · #1 of 2 lakes in the county · 5.6 ft clear · Mesotrophic · 12 acres · from B
Mesotrophic

Unnamed Lake in Nicollet County, Minnesota has a water quality grade of A (Excellent). Water clarity: 5.6 ft visibility. Phosphorus: 14.5 µg/L. Chlorophyll-a (algae): 5.9 µg/L. Maximum depth: 35 ft. Surface area: 12.1 acres.

Clarity
5.6 ft
Typical in August
71°F
Max depth
35 ft
Area
12 acres
Type
Mesotrophic
Trend
Improving
Public access
Yes
Ice-out
Mar 27
Open water
250 days

Next lake in Nicollet County

COak Leaf Lake3.9 ft clear · Nicollet CountyView →
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Unnamed Lake is a 12-acre mesotrophic lake in Nicollet County, Minnesota with a maximum depth of 35 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including black crappie, bluegill, and common carp. Public access is available with 1 public boat landing. Compared to the 1 other monitored lakes in Nicollet County, Unnamed Lake ranks #1 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Low algae

Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.

Excellent for swimming, crystal clear water with minimal algae

Compare the safest swimming lakes near Mankato

Get alerts for Unnamed Lake

Water Quality Grade: A (Excellent)

Murky, only visible to about 5.6 ft. Phosphorus level: 14.5 µg/L. Chlorophyll-a: 5.9 µg/L. Trophic State Index: 48.

MetricValueGrade
Water Clarity (Secchi Depth)5.6 ftNot graded
Phosphorus14.5 µg/LGood
Chlorophyll-a (Algae)5.9 µg/LGood
Trophic State Index (TSI)48Mesotrophic

Moderate nutrients, good water quality

Where to stay near Unnamed Lake

Compare lakeside cabins, hotels, and vacation rentals near Unnamed Lake in Nicollet 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 Unnamed 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

Unnamed Lake typically sits around 71°F at the surface in August. Summer average is about 69°F. Usually warmest in Aug (about 71°F) and coldest in May (about 59°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
59°
Jun
66°
Jul
69°
Aug
71°
Sep
69°
Oct
64°
Nov
Dec

Typical surface water temperature by month, from 285 field readings (20162025) via the EPA Water Quality Portal. See the full Unnamed Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth35 ft
Surface Area12 acres
Shoreline Length0.5 mi
Public AccessYes

Recreation & Access

1
Boat Landings
Yes
Public Access
  • St. PeterPublic

Fish Species

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

Fishing Unnamed Lake

DNR Fisheries Survey Summary

1 survey on file from MN DNR Fisheries. Most recent: 1999-06-03 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Yellow Perch17.000.1 lb
Bluegill8.670.27 lb
Green Sunfish0.670.1 lb
Largemouth Bass0.670.04 lb
Black Crappie0.330.53 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

17 fish · 58 in · 1999-06-03
9505678

Bluegill

26 fish · 49 in · 1999-06-03
1160trophy 10456789

Green Sunfish

2 fish · 36 in · 1999-06-03
103456

Largemouth Bass

2 fish · 45 in · 1999-06-03
1045

From the 1999-06-03 survey

Hallet's Pond is a 12-acre urban pond, formerly a gravel pit, located in the city of St. Peter, and currently functions as a stormwater detention basin. Currently there is no public access to the lake, but the city has purchased property adjacent to the lake and future plans may include the development of public…

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 Unnamed Lake. 2 reports on file.

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

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.257 m/yr6
Phosphorus Declining+12 µg/L/yr2
Chlorophyll-a Improving-0.3 µg/L/yr3
See year-by-year chart →

Ice Season

Historical ice data from Minnesota DNR (38 observations).

Typical Ice-Out
Mar 27
Typical Ice-In
Dec 2

Estimated open water season: 250 days

EarliestLatest
Ice-Out2017-02-22 (2017)2018-04-23 (2018)
Ice-In2014-11-18 (2014)2024-01-08 (2024)

Most recent ice-out: 2023-04-09

Regulated Pollution Sources Nearby

2 EPA-permitted facilities operate within about 5 miles of Unnamed Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 2 facilities have a reported Clean Water Act violation in the past three years.

  • Saint Peter Wwtp
    Saint Peter · 0.2 mi away · NPDES MN0022535
    MajorRecent violation
  • Covia Solutions Llc - Ottawa Plant
    Le Sueur · 2.3 mi away · NPDES MN0001716
    Recent violation

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.

County Ranking

Ranked #1 of 2 lakes in Nicollet County

Nearby Lakes in Nicollet County

Frequently asked questions about Unnamed Lake

What is the water quality grade for Unnamed Lake?

Unnamed Lake in Nicollet County, Minnesota has a water quality grade of A (Excellent). Water clarity: 5.6 ft visibility. Phosphorus: 14.5 µg/L. Chlorophyll-a (algae): 5.9 µg/L. Maximum depth: 35 ft. Surface area: 12.1 acres.

Is Unnamed Lake safe to swim in?

Excellent for swimming, crystal clear water with minimal algae. Unnamed Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 5.9 µg/L. Always check local health department advisories before swimming.

What is the water temperature of Unnamed Lake?

Unnamed Lake typically sits around 71°F at the surface in August, from 285 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.

How deep is Unnamed Lake?

Unnamed Lake has a maximum depth of 35 feet. The lake covers 12.1 acres.

What fish are in Unnamed Lake?

Fish species found in Unnamed Lake include black crappie, bluegill, common carp, green sunfish, largemouth bass, walleye. Unnamed Lake is located in Nicollet County, Minnesota.

When does Unnamed Lake thaw?

Unnamed Lake typically has ice-out around Mar 27. Ice typically forms around Dec 2. The open water season is approximately 250 days.

Are there boat ramps on Unnamed Lake?

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

Where this data comes from

133 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 WaterMNPCA133 samples · 2020–2025

Analytical methods

  • Field measurement/observation, generic method
  • Phosphorus by Colorimetry
  • 10200 H ~ Chlorophyll a-b-c Determination
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

Regulated discharger data from EPA ECHO (ICIS-NPDES)

Lake details from Minnesota DNR LakeFinder

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

Ice data from Minnesota DNR Climate