Leo Lake
Leo Lake in Cook County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 15 ft visibility. Maximum depth: 28 ft. Surface area: 102.4 acres.
- Clarity
- 15 ft
- Typical in August
- 73°F
- Max depth
- 28 ft
- Area
- 102 acres
- Trend
- ↓ Declining
- Public access
- Yes
Next lake in Cook County
Why Leo 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 Leo 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.
Leo Lake is a 102-acre lake in Cook County, Minnesota with a maximum depth of 28 feet (17-foot average). Overall water quality is declining over recent sampling years. The lake supports 3 documented fish species including green sunfish, rainbow trout, and smallmouth bass. Public access is available.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-09. 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 Leo Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Crystal clear, you can see 15 ft down. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Leo Lake
Compare lakeside cabins, hotels, and vacation rentals near Leo 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 Leo Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Leo Lake typically sits around 73°F at the surface in August. Summer average is about 69°F. Usually warmest in Aug (about 73°F) and coldest in May (about 50°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 16 field readings (2011–2025) via the EPA Water Quality Portal. See the full Leo Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 28 ft |
| Average Depth | 16.7 ft |
| Surface Area | 102 acres |
| Shoreline Length | 2.1 mi |
| Littoral Zone | 37% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Leo Lake
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2025-09-16 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 16.90 | — |
| Green Sunfish | 16.57 | 0.07 lb |
| Smallmouth Bass | 10.88 | 1.09 lb |
| Brook Trout | 3.27 | 0.74 lb |
| SPT | 2.86 | 1.01 lb |
| IOD | 2.85 | — |
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.
Green Sunfish
Smallmouth Bass
Brook Trout
From the 2025-09-16 survey
Leo Lake is a 102-acre lake with a maximum depth of 28.0 ft and located approximately 30 miles north of Grand Marais in Cook County, Minnesota. Access to the lake requires a steep, short carry-down off the Hungry Jack Lake Road. Leo Lake has been managed for stream trout since the 1930's, with rainbow trout stocked…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Leo Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — LeoFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Leo (1831)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — LeoFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — LeoPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.101 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.43 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +0.07 µg/L/yr | 6 |
EPA Impairment Status
Leo 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 MN16-0239-00 · Official waterbody report · Matched by proximity (2.74 km)
Graded lakes near Leo Lake
Leo Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Cook County
Frequently asked questions about Leo Lake
What is the water quality grade for Leo Lake?
- Leo Lake in Cook County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 15 ft visibility. Maximum depth: 28 ft. Surface area: 102.4 acres.
Is Leo Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Leo 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 Leo Lake?
- Leo Lake typically sits around 73°F at the surface in August, from 16 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Leo Lake?
- Leo Lake has a maximum depth of 28 feet and an average depth of 16.7 feet. The lake covers 102.4 acres.
What fish are in Leo Lake?
- Fish species found in Leo Lake include green sunfish, rainbow trout, smallmouth bass. Leo Lake is located in Cook County, Minnesota.
Explore Leo Lake across LakeGrade
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Where this data comes from
27 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
MNPCA27 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