Loon Lake
Jackson County, Minnesota708 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Loon Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- 2 aquatic invasives
- 8 ft max depth
- Public access
- Limited data
Loon Lake in Jackson County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. 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.
Minnesota DNR's Standard Survey on July 8, 2024 caught 21.33 walleye per gill net at Loon Lake. Length samples in the latest survey that recorded them ran 6–7 inches. DNR survey details →
Loon Lake is a 708-acre highly nutrient-loaded hypereutrophic lake in Jackson County, Minnesota with a maximum depth of 8 feet. 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. Methodology: how these readings are compared.
What Loon Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
- Fishing18 species recorded
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Loon Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Loon Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Loon Lake
These are the measurements Minnesota PCA publishes for Loon Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 0.9 ft of visibility. Phosphorus 274 µg/L. Chlorophyll-a 110 µg/L. TSI 80.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 0.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 274µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 110µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 80 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Loon Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Loon Lake typically sits around 73°F at the surface in September. 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.
Column height runs from this lake’s coldest month (47°F) to its warmest (81°F).
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 →
Minnesota DNR's Standard Survey on July 8, 2024 caught 21.33 walleye per gill net at Loon Lake. Length samples in the latest survey that recorded them ran 6–7 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Loon Lake’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
18 surveys on file from MN DNR Fisheries. Most recent: 2024-10-09 (Targeted Survey).
18 surveys on file · most recent 2024-10-09 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 55.71 | 4–13 in 2024-07-08 | 0.46 lb |
| Walleye | 23.39 | 6–7 in 2024-10-09 | 1.79 lb |
| Fathead Minnow | 20.57 | ||
| Largemouth Bass | 13.99 | 10 in 2024-07-08 | 1.71 lb |
| Green Sunfish | 9.52 | 4–5 in 2012-06-18 | 0.17 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
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
Lake Details
Max depth
8 ft
Surface area
708 acres
Shoreline
6.3 mi
Littoral zone
100%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
31 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,398 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Loon LakePublic
- Loon Lake (East)Public
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Loon Lake are listed below.
Top-rated places to stay near Loon Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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 →
Follow Loon Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fish Species
Click a species to see every 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.
Water quality readings over time
2 seasons of samples on record (2022–2023). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
Phosphorus
Improving-65.5 µg/L/yr2 years
Chlorophyll-a
Improving-14.6 µg/L/yr2 years
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
Designated uses not supporting: Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN32-0020-00 · Official waterbody report
Nearby Lakes in Jackson County
Frequently asked questions about Loon Lake
Where is Loon Lake?
- Loon Lake is a lake in Jackson County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Loon Lake?
- Loon Lake in Jackson County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. 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?
- Nutrient and algae readings are not a swimming clearance. Loon Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Loon Lake?
- Loon Lake typically sits around 73°F at the surface in September, 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.
What did the DNR fisheries survey find at Loon Lake?
- Minnesota DNR's Standard Survey on July 8, 2024 caught 21.33 walleye per gill net at Loon Lake. Length samples in the latest survey that recorded them ran 6–7 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Loon Lake’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
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.
Can I fish at Loon Lake?
- Loon Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Loon Lake across LakeQuality
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Jackson County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
State Parks Near Loon Lake
Other Lakes in Minnesota
Hypereutrophic Lakes in Minnesota
Compare Loon Lake With Nearby Lakes
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)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from 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