Caribou Lake
Caribou Lake in St. Louis County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 10.5 ft visibility. Maximum depth: 21 ft. Surface area: 538.57 acres.
- Clarity
- 10.5 ft
- Typical in August
- 74°F
- Max depth
- 21 ft
- Area
- 539 acres
- Public access
- Yes
- Ice-out
- Apr 23
- Open water
- 215 days
Next lake in St. Louis County
Why Caribou Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Caribou Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Caribou Lake is a 539-acre lake in St. Louis County, Minnesota with a maximum depth of 21 feet (9-foot average). The lake supports 11 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-11-16. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Caribou Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Good clarity, visible to about 10.5 ft. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Caribou Lake
Compare lakeside cabins, hotels, and vacation rentals near Caribou Lake in St. Louis 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
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Water Temperature
Caribou Lake typically sits around 74°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 75°F) and coldest in Nov (about 52°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 25 field readings (2016–2023) via the EPA Water Quality Portal. See the full Caribou Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Caribou Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was low (14,454 cells/mL) on June 6, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 21 ft |
| Average Depth | 9 ft |
| Surface Area | 539 acres |
| Shoreline Length | 5.6 mi |
| Littoral Zone | 90% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Caribou Lake (West)Public
- Caribou Lake (East)Public
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Caribou Lake
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2025-06-30 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluntnose Minnow | 29.55 | — |
| Largemouth Bass | 17.79 | 1.17 lb |
| Bluegill | 16.83 | 0.21 lb |
| Black Crappie | 6.48 | 0.19 lb |
| CNM | 5.43 | — |
| MTS | 5.17 | — |
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.
Largemouth Bass
Bluegill
Black Crappie
From the 2025-06-30 survey
A targeted survey of nearshore fish species in Caribou Lake was conducted on June 30th-July 3rd, 2025, by Lake Biological Monitoring and Assessment (LBMA) program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing, mini-fyke nets, and seining with a 50-foot or…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Caribou Lake. 5 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — CaribouFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Caribou (0451)Aquatic Plant Report · MN DNR LakeFinder
- —Aquatic Plant Report — Caribou (0513)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — CaribouFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — CaribouPublic Water Access Sites · MN DNR LakeFinder
Ice Season
Historical ice data from Minnesota DNR (10 observations).
Estimated open water season: 215 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2005-04-11 (2005) | 2008-05-03 (2008) |
| Ice-In | 2006-11-02 (2006) | 2004-11-29 (2004) |
Most recent ice-out: 2020-04-25
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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN69-0489-00 · Official waterbody report
Nearby Lakes in St. Louis County
Frequently asked questions about Caribou Lake
What is the water quality grade for Caribou Lake?
- Caribou Lake in St. Louis County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 10.5 ft visibility. Maximum depth: 21 ft. Surface area: 538.57 acres.
Is Caribou Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Caribou Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
What is the water temperature of Caribou Lake?
- Caribou Lake typically sits around 74°F at the surface in August, from 25 EPA Water Quality Portal field readings (2016–2023). That is a typical value for the month, not a live reading.
How deep is Caribou Lake?
- Caribou Lake has a maximum depth of 21 feet and an average depth of 9 feet. The lake covers 538.57 acres.
What fish are in Caribou Lake?
- Fish species found in Caribou Lake include black bullhead, black crappie, bluegill, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, white sucker, yellow perch. Caribou Lake is located in St. Louis County, Minnesota.
When does Caribou Lake thaw?
- Caribou Lake typically has ice-out around Apr 23. Ice typically forms around Nov 24. The open water season is approximately 215 days.
Does Caribou Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Caribou Lake (clouds, ice, or an off-season gap). The most recent reading was low (14,454 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Caribou Lake?
- Caribou Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Caribou Lake (West), Caribou Lake (East). Public access is listed as yes.
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Where this data comes from
11 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA11 samples · 2023
Analytical methods
- Field measurement/observation, generic method
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