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LakeQuality

Caribou Lake

A
Grade A — Excellent
Excellent · #9 of 44 lakes in the county · 6.9 ft clear · Mesotrophic · 68 acres · from B
Mesotrophic

Caribou Lake in Cook County, Minnesota has a water quality grade of A (Excellent). Water clarity: 6.9 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 6.2 µg/L. Surface area: 68.31 acres.

Clarity
6.9 ft
Typical in August
72°F
Area
68 acres
Type
Mesotrophic
Trend
Declining
Public access
Yes

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AWard Lake5.6 ft clear · Cook CountyView →
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Caribou Lake is a 68-acre mesotrophic lake in Cook County, Minnesota. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 1 documented fish species including white sucker. Public access is available with 1 public boat landing. Compared to the 43 other monitored lakes in Cook County, Caribou Lake ranks #9 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-11. 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 Ely

Get alerts for Caribou Lake

Water Quality Grade: A (Excellent)

Moderate clarity, visible to about 6.9 ft. Phosphorus level: 15 µg/L. Chlorophyll-a: 6.2 µg/L. Trophic State Index: 47.

MetricValueGrade
Water Clarity (Secchi Depth)6.9 ftNot graded
Phosphorus15 µg/LGood
Chlorophyll-a (Algae)6.2 µg/LGood
Trophic State Index (TSI)47Mesotrophic

Moderate nutrients, good water quality

Where to stay near Caribou Lake

Compare lakeside cabins, hotels, and vacation rentals near Caribou Lake in Cook 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 Caribou 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

Caribou Lake typically sits around 72°F at the surface in August. Summer average is about 70°F. Usually warmest in Jul (about 74°F) and coldest in Jun (about 64°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
Jun
64°
Jul
74°
Aug
72°
Sep
74°
Oct
Nov
Dec

Typical surface water temperature by month, from 37 field readings (20102025) via the EPA Water Quality Portal. See the full Caribou Lake water temperature breakdown →

Lake Details

CharacteristicValue
Surface Area68 acres
Shoreline Length2 mi
Littoral Zone100%
Public AccessYes

The available depth estimate for Caribou Lake is shallower than its measured water clarity, which cannot be right, so no depth is shown.

Lake Size & Watershed

Watershed (drainage) area
11 sq mi
Elevation
1,365 ft

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

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Caribou LakePublic

Fish Species

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

Fishing Caribou Lake

DNR Fisheries Survey Summary

1 survey on file from MN DNR Fisheries. Most recent: 1995-09-18 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
White Sucker14.500.3 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.

White Sucker

29 fish · 614 in · 1995-09-18
84067891011121314

From the 1995-09-18 survey

Agnes Lake presently has no apparent fishery value. Black crappie, which were apparently abundant in the early-1970's, appear to have disappeared.

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 Caribou Lake. 1 report 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 Declining-0.054 m/yr6
Phosphorus Declining+0.5 µg/L/yr6
Chlorophyll-a Declining+0.33 µg/L/yr6
See year-by-year chart →

EPA Impairment Status

Caribou Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Mercury

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN16-0360-00 · Official waterbody report

Regulated Pollution Sources Nearby

1 EPA-permitted facility operate within about 5 miles of Caribou Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.

  • Caribou Highlands Lodge Wwtp
    Lutsen · 4.1 mi away · NPDES MN0053252
    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 #9 of 44 lakes in Cook County

Nearby Lakes in Cook County

Frequently asked questions about Caribou Lake

What is the water quality grade for Caribou Lake?

Caribou Lake in Cook County, Minnesota has a water quality grade of A (Excellent). Water clarity: 6.9 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 6.2 µg/L. Surface area: 68.31 acres.

Is Caribou Lake safe to swim in?

Excellent for swimming, crystal clear water with minimal algae. Caribou Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 6.2 µg/L. Always check local health department advisories before swimming.

What is the water temperature of Caribou Lake?

Caribou Lake typically sits around 72°F at the surface in August, from 37 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.

How deep is Caribou Lake?

The available depth estimate for Caribou Lake is shallower than its measured water clarity, which cannot be right, so no depth is shown. The lake covers 68.31 acres.

What fish are in Caribou Lake?

Fish species found in Caribou Lake include white sucker. Caribou Lake is located in Cook County, Minnesota.

Are there boat ramps on Caribou Lake?

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

Where this data comes from

340 measurements from 5 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA340 samples · 2020–2025

Analytical methods

  • Field measurement/observation, generic method
  • Phosphorus by Two Reagent Colorimetry
  • 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (5)

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