Cowhorn Lake
Cowhorn Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 2.8 ft visibility.
- Clarity
- 2.8 ft
- Max depth
- ~49 ft est.
- Trend
- ↑ Improving
- Public access
- Yes
Next lake in Itasca County
Why Cowhorn 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 Cowhorn 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.
Cowhorn Lake is a lake in Itasca County, Minnesota with an estimated average depth of about 49 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-07-28. 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 Cowhorn Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Very murky, less than 2.8 ft of visibility. Trophic State Index: 63.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.8 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Cowhorn Lake
Compare lakeside cabins, hotels, and vacation rentals near Cowhorn Lake in Itasca 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 Cowhorn Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~49 ft est. |
| Average Depth | ~7 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Minnesota has not published bathymetry for Cowhorn Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Cowhorn LakePublic
- CasperPublic
Fishing Cowhorn Lake
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Cowhorn Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Aquatic Plant Report — Cowhorn (0552)Aquatic Plant Report · MN DNR LakeFinder
- —Aquatic Plant Report — Cowhorn (2054)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — CowhornPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.041 m/yr | 6 |
EPA Impairment Status
Cowhorn 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 MN31-0198-00 · Official waterbody report · Matched by proximity (2.5 km)
Graded lakes near Cowhorn Lake
Cowhorn Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Itasca County
Frequently asked questions about Cowhorn Lake
What is the water quality grade for Cowhorn Lake?
- Cowhorn Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 2.8 ft visibility.
Is Cowhorn Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Cowhorn Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
How deep is Cowhorn Lake?
- No published bathymetric survey covers Cowhorn Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 49 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Cowhorn Lake?
- Cowhorn Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Cowhorn Lake, Casper. Public access is listed as yes.
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Where this data comes from
8 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA8 samples · 2020–2025
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