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LakeQuality

Cannon Lake

F
Grade F — Algae-prone
Algae-prone · #12 of 14 lakes in the county · 4.1 ft clear · Eutrophic · 1,593 acres · from D
Limited DataEutrophic

Cannon Lake in Rice County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 4.1 ft visibility. Phosphorus: 244 µg/L. Chlorophyll-a (algae): 46.5 µg/L. Maximum depth: 15 ft. Surface area: 1593.25 acres.

Clarity
4.1 ft
Max depth
15 ft
Area
1,593 acres
Type
Eutrophic
Public access
Yes
Ice-out
Mar 31
Open water
242 days

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

Next lake in Rice County

FWells Lake2 ft clear · Rice CountyView →
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Free interactive depth-contour map of Cannon Lake, reaching a maximum surveyed depth of 15 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.

Cannon Lake is a 1,593-acre productive, nutrient-rich eutrophic lake in Rice County, Minnesota with a maximum depth of 15 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 1 public boat landing. Compared to the 13 other monitored lakes in Rice County, Cannon Lake ranks #12 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-09. 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 Cannon Lake

Water Quality Grade: F (Algae-prone)

Murky, only visible to about 4.1 ft. Phosphorus level: 244 µg/L. Chlorophyll-a: 46.5 µg/L. Trophic State Index: 69.

MetricValueGrade
Water Clarity (Secchi Depth)4.1 ftNot graded
Phosphorus244 µg/LPoor
Chlorophyll-a (Algae)46.5 µg/LPoor
Trophic State Index (TSI)69Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Cannon Lake

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

Top-rated places to stay near Cannon 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 Depth15 ft
Surface Area1,593 acres
Shoreline Length12 mi
Littoral Zone100%
Public AccessYes

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Cannon LakePublic

Fish Species

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

Fishing Cannon 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.

flowering rush

Ice Season

Historical ice data from Minnesota DNR (74 observations).

Typical Ice-Out
Mar 31
Typical Ice-In
Nov 28

Estimated open water season: 242 days

EarliestLatest
Ice-Out2024-02-28 (2024)2018-04-29 (2018)
Ice-In1991-11-03 (1991)1998-12-19 (1998)

Most recent ice-out: 2026-03-26

EPA Impairment Status

Cannon 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 MN66-0008-00 · Official waterbody report

County Ranking

Ranked #12 of 14 lakes in Rice County

Nearby Lakes With Higher Grades

Cannon Lake holds Grade F. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.

Nearby Lakes in Rice County

FWells Lake2 ft clear · HypereutrophicCompareView →
FRoberds Lake2.5 ft clear · HypereutrophicCompareView →
FCedar Lake2 ft clear · EutrophicCompareView →
FFrench Lake1.7 ft clear · HypereutrophicCompareView →
CKelly Lake8.2 ft clear · EutrophicView →DDudley Lake9 ft clear · EutrophicView →

Frequently asked questions about Cannon Lake

What is the water quality grade for Cannon Lake?

Cannon Lake in Rice County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 4.1 ft visibility. Phosphorus: 244 µg/L. Chlorophyll-a (algae): 46.5 µg/L. Maximum depth: 15 ft. Surface area: 1593.25 acres.

Is Cannon 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. Cannon Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 46.5 µg/L. Always check local health department advisories before swimming.

How deep is Cannon Lake?

Cannon Lake has a maximum depth of 15 feet. The lake covers 1593.25 acres.

What fish are in Cannon Lake?

Fish species found in Cannon Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, bowfin (dogfish), channel catfish, common carp, freshwater drum, largemouth bass, northern pike, pumpkinseed, river carpsucker, walleye, white bass, white sucker, yellow bullhead, yellow perch. Cannon Lake is located in Rice County, Minnesota.

When does Cannon Lake thaw?

Cannon Lake typically has ice-out around Mar 31. Ice typically forms around Nov 28. The open water season is approximately 242 days.

Are there boat ramps on Cannon Lake?

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

Eutrophic Lakes in Minnesota

Where this data comes from

12 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 WaterMNPCA12 samples · 2025

Analytical methods

  • Field measurement/observation, generic method
  • Phosphorus by Two Reagent Colorimetry
  • 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
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