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LakeQuality

Fox Lake

F
Grade F — Algae-prone
Algae-prone · #6 of 12 lakes in the county · 1 ft clear · Hypereutrophic · 951 acres
Limited DataHypereutrophic

Fox Lake in Martin County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1 ft visibility. Phosphorus: 197 µg/L. Chlorophyll-a (algae): 65.8 µg/L. Maximum depth: 20 ft. Surface area: 951.02 acres.

Clarity
1 ft
Typical in August
75°F
Max depth
20 ft
Area
951 acres
Type
Hypereutrophic
Public access
Yes
Ice-out
Mar 22
Open water
271 days

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

Next lake in Martin County

FTemperance Lake0.7 ft clear · Martin CountyView →
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Free interactive depth-contour map of Fox Lake, reaching a maximum surveyed depth of 20 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.

Fox Lake is a 951-acre highly nutrient-loaded hypereutrophic lake in Martin County, Minnesota with a maximum depth of 20 feet. Water quality is graded F based on 2 sampling years through 2025. The lake supports 17 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 2 public boat landings. Compared to the 11 other monitored lakes in Martin County, Fox Lake ranks #6 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

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.

Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom

Compare the safest swimming lakes near Mankato

Get alerts for Fox Lake

Water Quality Grade: F (Algae-prone)

Very murky, less than 1 ft of visibility. Phosphorus level: 197 µg/L. Chlorophyll-a: 65.8 µg/L. Trophic State Index: 76.

MetricValueGrade
Water Clarity (Secchi Depth)1 ftNot graded
Phosphorus197 µg/LPoor
Chlorophyll-a (Algae)65.8 µg/LPoor
Trophic State Index (TSI)76Hypereutrophic

Very high nutrients, dense algae, poor clarity

Where to stay near Fox Lake

Compare lakeside cabins, hotels, and vacation rentals near Fox Lake in Martin 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 Fox Lake are listed below.

Top-rated places to stay near Fox 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

Fox Lake typically sits around 75°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 79°F) and coldest in May (about 57°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
57°
Jun
73°
Jul
79°
Aug
75°
Sep
70°
Oct
Nov
Dec

Typical surface water temperature by month, from 104 field readings (20172025) via the EPA Water Quality Portal. See the full Fox Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth20 ft
Surface Area951 acres
Shoreline Length11.3 mi
Littoral Zone82%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
15 sq mi
Elevation
1,230 ft

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

Recreation & Access

2
Boat Landings
Yes
Public Access
  • Fox Lake (Northeast)Public
  • Fox Lake (Southeast)Public

Fish Species

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

Fishing Fox Lake

Ice Season

Historical ice data from Minnesota DNR (13 observations).

Typical Ice-Out
Mar 22
Typical Ice-In
Dec 18

Estimated open water season: 271 days

EarliestLatest
Ice-Out2017-03-12 (2017)2018-04-27 (2018)
Ice-In2007-11-22 (2007)2004-12-21 (2004)

Most recent ice-out: 2018-04-27

EPA Impairment Status

Fox Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Impaired biota (cause unknown)Nutrients (phosphorus, nitrogen)

Source: EPA ATTAINS assessment unit MN46-0109-00 · Official waterbody report

Regulated Pollution Sources Nearby

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

  • Welcom Wwtf
    Welcome · 3.6 mi away · NPDES MN0021296

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 #6 of 12 lakes in Martin County

Nearby Lakes in Martin County

Frequently asked questions about Fox Lake

What is the water quality grade for Fox Lake?

Fox Lake in Martin County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1 ft visibility. Phosphorus: 197 µg/L. Chlorophyll-a (algae): 65.8 µg/L. Maximum depth: 20 ft. Surface area: 951.02 acres.

Is Fox Lake safe to swim in?

Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Fox Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 65.8 µg/L. Always check local health department advisories before swimming.

What is the water temperature of Fox Lake?

Fox Lake typically sits around 75°F at the surface in August, from 104 EPA Water Quality Portal field readings (2017–2025). That is a typical value for the month, not a live reading.

How deep is Fox Lake?

Fox Lake has a maximum depth of 20 feet. The lake covers 951.02 acres.

What fish are in Fox Lake?

Fish species found in Fox Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, channel catfish, common carp, freshwater drum, green sunfish, hybrid crappie, hybrid sunfish, largemouth bass, muskellunge, quillback, walleye, white crappie, yellow bullhead, yellow perch. Fox Lake is located in Martin County, Minnesota.

When does Fox Lake thaw?

Fox Lake typically has ice-out around Mar 22. Ice typically forms around Dec 18. The open water season is approximately 271 days.

Are there boat ramps on Fox Lake?

Fox Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Fox Lake (Northeast), Fox Lake (Southeast). Public access is listed as yes.

Hypereutrophic Lakes in Minnesota

Where this data comes from

23 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 WaterMNPCA23 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

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

Ice data from Minnesota DNR Climate