Loon Lake
Loon Lake in Jackson County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 0.9 ft visibility. Phosphorus: 274 µg/L. Chlorophyll-a (algae): 110 µg/L. Maximum depth: 8 ft. Surface area: 707.68 acres.
- Clarity
- 0.9 ft
- Typical in August
- 76°F
- Max depth
- 8 ft
- Area
- 708 acres
- Type
- Hypereutrophic
- Trend
- ↑ Improving
- Public access
- Yes
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Loon Lake →
Next lake in Jackson County
Loon Lake is a 708-acre highly nutrient-loaded hypereutrophic lake in Jackson County, Minnesota with a maximum depth of 8 feet. Water quality is graded F based on 2 sampling years through 2022. Overall water quality is improving over recent sampling years. The lake supports 18 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 2 public boat landings. Compared to the 5 other monitored lakes in Jackson County, Loon Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-09-07. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
Very murky, less than 0.9 ft of visibility. Phosphorus level: 274 µg/L. Chlorophyll-a: 110 µg/L. Trophic State Index: 80.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.9 ft | Not graded |
| Phosphorus | 274 µg/L | Poor |
| Chlorophyll-a (Algae) | 110 µg/L | Poor |
| Trophic State Index (TSI) | 80 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Loon Lake
Compare lakeside cabins, hotels, and vacation rentals near Loon Lake in Jackson 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Loon Lake are listed below.
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 →
Water Temperature
Loon Lake typically sits around 76°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 81°F) and coldest in May (about 47°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 13 field readings (2022–2022) via the EPA Water Quality Portal. See the full Loon Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 8 ft |
| Surface Area | 708 acres |
| Shoreline Length | 6.3 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Loon LakePublic
- Loon Lake (East)Public
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Loon Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
DNR Fisheries Survey Summary
18 surveys on file from MN DNR Fisheries. Most recent: 2024-10-09 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 55.71 | 0.46 lb |
| Walleye | 23.39 | 1.79 lb |
| Fathead Minnow | 20.57 | — |
| Largemouth Bass | 13.99 | 1.71 lb |
| Green Sunfish | 9.52 | 0.17 lb |
| OSS | 6.14 | 0.03 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.
Black Bullhead
Walleye
Largemouth Bass
Green Sunfish
From the 2024-10-09 survey
Loon Lake is a 738-acre class 43 lake with a maximum depth of 8 feet, located in Jackson County, approximately 10 miles south of the City of Lakefield near the Iowa-Minnesota border. The surrounding land use of Loon Lake is largely agricultural, resulting in nutrient rich, turbid water. Loon Lake is managed primarily…
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
- —Fish Stocking History — LoonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — LoonPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.02 m/yr | 2 |
| Phosphorus | ↑ Improving | -65.5 µg/L/yr | 2 |
| Chlorophyll-a | ↑ Improving | -14.6 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Loon Lake is a man-made reservoir impounded by the Loon Lake (completed 1935), built primarily for recreation on the LOON CREEK; gravity-type dam, 8 ft tall and 30 ft long.
- Surface area
- 707 ac
- Normal storage
- 3,000 ac-ft
- Max storage
- 5,000 ac-ft
- Drainage area
- 32 sq mi
- Hazard class
- Low
- Owner
- County of Jackson
Source: USACE National Inventory of Dams, NID ID MN00116 · Operator website
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 MN32-0020-00 · Official waterbody report
County Ranking
Ranked #5 of 6 lakes in Jackson County
Nearby Lakes With Higher Grades
Loon Lake holds Grade F. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Jackson County
Frequently asked questions about Loon Lake
What is the water quality grade for Loon Lake?
- Loon Lake in Jackson County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 0.9 ft visibility. Phosphorus: 274 µg/L. Chlorophyll-a (algae): 110 µg/L. Maximum depth: 8 ft. Surface area: 707.68 acres.
Is Loon Lake safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Loon Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 110 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Loon Lake?
- Loon Lake typically sits around 76°F at the surface in August, from 13 EPA Water Quality Portal field readings (2022–2022). That is a typical value for the month, not a live reading.
How deep is Loon Lake?
- Loon Lake has a maximum depth of 8 feet. The lake covers 707.68 acres.
What fish are in Loon Lake?
- Fish species found in Loon Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, channel catfish, common carp, freshwater drum, green sunfish, largemouth bass, northern pike, orangespotted sunfish, shortnose gar, walleye, white bass, white sucker, yellow bass, yellow bullhead, yellow perch. Loon Lake is located in Jackson County, Minnesota.
Are there boat ramps on Loon Lake?
- Loon Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Loon Lake, Loon Lake (East). Public access is listed as yes.
Explore Loon Lake across LakeGrade
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Species activity outlook by water temperature and season
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Where this data comes from
15 measurements from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA15 samples · 2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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