Loon Lake
Loon Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 14 ft visibility. Maximum depth: 69 ft. Surface area: 230.99 acres.
- Clarity
- 14 ft
- Max depth
- 69 ft
- Area
- 231 acres
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 18
- Open water
- 222 days
Next lake in Itasca County
Why Loon 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 Loon 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.
Loon Lake is a 231-acre lake in Itasca County, Minnesota with a maximum depth of 69 feet. Overall water quality is improving over recent sampling years. The lake supports 12 documented fish species including black crappie, bluegill, and bowfin (dogfish). Public access is available with 3 public boat landings.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-08-20. Grade methodology: LakeGrade methodology.
Watch Loon Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Loon Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Good clarity, visible to about 14 ft. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Loon Lake
Compare lakeside cabins, hotels, and vacation rentals near Loon 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 Loon 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
| Characteristic | Value |
|---|---|
| Maximum Depth | 69 ft |
| Surface Area | 231 acres |
| Shoreline Length | 3.6 mi |
| Littoral Zone | 48% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Loon LakePublic
- Jay Gould LakePublic
- Long LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Loon Lake
DNR Fisheries Survey Summary
8 surveys on file from MN DNR Fisheries. Most recent: 2025-08-06 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 25.82 | 0.12 lb |
| Largemouth Bass | 13.83 | 1.14 lb |
| Tullibee (Cisco) | 11.73 | 1.21 lb |
| Yellow Perch | 6.70 | 0.14 lb |
| Pumpkinseed | 3.99 | 0.19 lb |
| Northern Pike | 3.91 | 2.05 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.
Bluegill
Largemouth Bass
Tullibee (Cisco)
Yellow Perch
From the 2025-08-06 survey
Temperature and dissolved oxygen (DO) measurements were collected from the deepest basin in Loon Lake on August 6th, 2025, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Cisco, also known as Tullibee, the most sensitive coldwater species present in this lake.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Loon Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — LoonFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Loon (0558)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — LoonPublic 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 | +0.096 m/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (34 observations).
Estimated open water season: 222 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-03-25 (2012) | 2013-05-14 (2013) |
| Ice-In | 2002-11-12 (2002) | 2001-12-07 (2001) |
Most recent ice-out: 2021-04-05
EPA Impairment Status
Loon 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 MN31-0571-00 · Official waterbody report
Graded lakes near Loon Lake
Loon Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Itasca County
Frequently asked questions about Loon Lake
What is the water quality grade for Loon Lake?
- Loon Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 14 ft visibility. Maximum depth: 69 ft. Surface area: 230.99 acres.
Is Loon Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Loon 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 Loon Lake?
- Loon Lake has a maximum depth of 69 feet. The lake covers 230.99 acres.
What fish are in Loon Lake?
- Fish species found in Loon Lake include black crappie, bluegill, bowfin (dogfish), hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, tullibee (cisco), walleye, yellow bullhead, yellow perch. Loon Lake is located in Itasca County, Minnesota.
When does Loon Lake thaw?
- Loon Lake typically has ice-out around Apr 18. Ice typically forms around Nov 26. The open water season is approximately 222 days.
Are there boat ramps on Loon Lake?
- Loon Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Loon Lake, Jay Gould Lake, Long Lake. Public access is listed as yes.
Explore Loon Lake across LakeGrade
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Itasca County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Mississippi Headwaters, ranked by water quality
Lakes in the Rainy Lake Watershed, ranked by water quality
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Loon Lake
Other Lakes in Minnesota
Oligotrophic Lakes in Minnesota
Where this data comes from
4 measurements from 2 monitoring stations, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA4 samples · 2020–2024
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (2)
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