Skip to main content
LakeQuality

Frost Lake

NR
Not yet rated
11 ft clear · Mesotrophic · 284 acres
Limited DataMesotrophic

Frost Lake in Cook County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 11 ft visibility. Maximum depth: 88 ft. Surface area: 283.91 acres.

Clarity
11 ft
Max depth
88 ft
Area
284 acres
Public access
No

Next lake in Cook County

NRKarl Lake8 ft clear · Cook CountyView →
Loading map…

Why Frost 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 Frost Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). 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.

Frost Lake is a 284-acre lake in Cook County, Minnesota with a maximum depth of 88 feet. Limited fish-species data available. No public access — the lake is private or restricted.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-08-14. Grade methodology: LakeGrade methodology.

Watch Frost Lake water quality

Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.

Swimming Safety

Not rated

Limited data

Not rated for swimming — there is not enough monitoring data to judge this lake

Compare the safest swimming lakes near Ely

Get alerts for Frost Lake

Water quality measurements for Frost Lake

These readings exist but do not meet the evidence bar for an A–F grade — see why.

Good clarity, visible to about 11 ft. Trophic State Index: 43.

MetricValueGrade
Water Clarity (Secchi Depth)11 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)43Mesotrophic

Moderate nutrients, good water quality

Where to stay near Frost Lake

Compare lakeside cabins, hotels, and vacation rentals near Frost 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 Frost 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 Depth88 ft
Surface Area284 acres
Shoreline Length4.2 mi
Littoral Zone22%
Public AccessNo

Lake Size & Watershed

Watershed (drainage) area
2 sq mi
Elevation
1,768 ft

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

Fishing Frost Lake

EPA Impairment Status

Frost 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 MN16-0571-00 · Official waterbody report

Nearby Lakes in Cook County

Frequently asked questions about Frost Lake

What is the water quality grade for Frost Lake?

Frost Lake in Cook County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 11 ft visibility. Maximum depth: 88 ft. Surface area: 283.91 acres.

Is Frost Lake safe to swim in?

Not rated for swimming — there is not enough monitoring data to judge this lake. Frost 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 Frost Lake?

Frost Lake has a maximum depth of 88 feet. The lake covers 283.91 acres.

Where this data comes from

1 measurement 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 WaterMNPCA1 sample · 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