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LakeQuality

High Island Lake

D
Grade D — Nutrient-rich
Nutrient-rich · #1 of 2 lakes in the county · 2.1 ft clear · Eutrophic · 1,340 acres · from F
Limited DataEutrophic

High Island Lake in Sibley County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 2.1 ft visibility. Phosphorus: 180 µg/L. Chlorophyll-a (algae): 14.6 µg/L. Maximum depth: 6.5 ft. Surface area: 1340.26 acres.

Clarity
2.1 ft
Typical in August
76°F
Max depth
6.5 ft
Area
1,340 acres
Type
Eutrophic
Public access
Yes
Ice-out
Apr 3
Open water
238 days

Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near High Island Lake

Next lake in Sibley County

FTitlow Lake0.3 ft clear · Sibley CountyView →
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High Island Lake is a 1,340-acre productive, nutrient-rich eutrophic lake in Sibley County, Minnesota with a maximum depth of 7 feet. Water quality is graded D based on 2 sampling years through 2025. The lake supports 11 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 1 other monitored lakes in Sibley County, High Island Lake ranks #1 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-24. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Limited data

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.

Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum

Compare the safest swimming lakes near Mankato

Get alerts for High Island Lake

Water Quality Grade: D (Nutrient-rich)

Very murky, less than 2.1 ft of visibility. Phosphorus level: 180 µg/L. Chlorophyll-a: 14.6 µg/L. Trophic State Index: 68.

MetricValueGrade
Water Clarity (Secchi Depth)2.1 ftNot graded
Phosphorus180 µg/LPoor
Chlorophyll-a (Algae)14.6 µg/LFair
Trophic State Index (TSI)68Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near High Island Lake

Compare lakeside cabins, hotels, and vacation rentals near High Island Lake in Sibley 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around High Island Lake are listed below.

Top-rated places to stay near High Island 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

High Island Lake typically sits around 76°F at the surface in August. Summer average is about 75°F. Usually warmest in Aug (about 76°F) and coldest in Sep (about 70°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
Jun
73°
Jul
Aug
76°
Sep
70°
Oct
Nov
Dec

Typical surface water temperature by month, from 8 field readings (20252025) via the EPA Water Quality Portal. See the full High Island Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth6.5 ft
Surface Area1,340 acres
Shoreline Length16.1 mi
Littoral Zone100%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
15 sq mi
Elevation
978 ft

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

Recreation & Access

1
Boat Landings
Yes
Public Access
  • High Island LakePublic

Fish Species

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

Fishing High Island Lake

Ice Season

Historical ice data from Minnesota DNR (32 observations).

Typical Ice-Out
Apr 3
Typical Ice-In
Nov 27

Estimated open water season: 238 days

EarliestLatest
Ice-Out2016-03-12 (2016)2018-04-30 (2018)
Ice-In2019-11-09 (2019)2015-12-17 (2015)

Most recent ice-out: 2023-04-13

EPA Impairment Status

High Island 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 MN72-0050-01 · Official waterbody report · Matched by proximity (0.72 km)

County Ranking

Ranked #1 of 2 lakes in Sibley County

Nearby Lakes in Sibley County

Frequently asked questions about High Island Lake

What is the water quality grade for High Island Lake?

High Island Lake in Sibley County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 2.1 ft visibility. Phosphorus: 180 µg/L. Chlorophyll-a (algae): 14.6 µg/L. Maximum depth: 6.5 ft. Surface area: 1340.26 acres.

Is High Island Lake safe to swim in?

Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. High Island Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 14.6 µg/L. Always check local health department advisories before swimming.

What is the water temperature of High Island Lake?

High Island Lake typically sits around 76°F at the surface in August, from 8 EPA Water Quality Portal field readings (2025–2025). That is a typical value for the month, not a live reading.

How deep is High Island Lake?

High Island Lake has a maximum depth of 6.5 feet. The lake covers 1340.26 acres.

What fish are in High Island Lake?

Fish species found in High Island Lake include black bullhead, black crappie, bluegill, common carp, freshwater drum, green sunfish, orangespotted sunfish, shortnose gar, walleye, white sucker, yellow perch. High Island Lake is located in Sibley County, Minnesota.

When does High Island Lake thaw?

High Island Lake typically has ice-out around Apr 3. Ice typically forms around Nov 27. The open water season is approximately 238 days.

Are there boat ramps on High Island Lake?

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

Compare High Island Lake With Nearby Lakes

Where this data comes from

9 measurements from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA9 samples · 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

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