Osakis Lake
Todd County, Minnesota6,389 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Osakis Lake. Here is what has been measured.
- Eutrophic
- Impaired · Impaired biota (cause unknown)
- zebra mussel
- 73 ft max depth
- Public access
Osakis Lake in Todd County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10.5 ft visibility. Phosphorus: 75 µg/L. Chlorophyll-a (algae): 9.6 µg/L. Maximum depth: 73 ft. Surface area: 6389.35 acres.
Minnesota DNR's Targeted Survey on August 25, 2025 caught 6.83 walleye per gill net at Osakis Lake. DNR survey details →
Free interactive depth-contour map of Osakis Lake, reaching a maximum surveyed depth of 60 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Osakis Lake is a 6,389-acre productive, nutrient-rich eutrophic lake in Todd County, Minnesota with a maximum depth of 73 feet (20-foot average). Overall water quality is improving over recent sampling years. The lake supports 18 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 3 public boat landings. Compared to the 7 other monitored lakes in Todd County, Osakis Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-14. Methodology: how these readings are compared.
At about 6,400 acres, Osakis Lake is large enough that where you stay decides which shore you see most of. It has 3 public boat landings, so a lakefront rental is not the only way to get a boat on the water. The median ice-out date is April 19, which is when the open-water season begins. For a place on the water, look through cabin and lake-house rentals near Osakis Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Osakis Lake is good for
From access and monitoring records, not editorial picks.
- Clear water10.5 ft of visibility
- Boat launch3 documented ramps
- Fishing18 species recorded
- Ice seasonIce-out around Apr 19
- Deep water73 ft surveyed max depth
- Big water6,389 acres
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. Osakis Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Osakis 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 Osakis Lake
These are the measurements Minnesota PCA publishes for Osakis Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 10.5 ft. Phosphorus 75 µg/L. Chlorophyll-a 9.6 µg/L. TSI 54.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 10.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 75µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 9.6µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 54 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Osakis Lake
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Targeted Survey on August 25, 2025 caught 6.83 walleye per gill net at Osakis Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Osakis Lake’s water-quality measurements separately, and the water-quality trend over 4 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: 2025-08-25 (Targeted Survey).
18 surveys on file · most recent 2025-08-25 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Yellow Perch | 22.89 | 5–8 in 2025-08-25 | 0.14 lb |
| Green Sunfish | 22.70 | 5 in 2018-08-13 | 0.14 lb |
| Bluegill | 18.50 | 3–9 in 2025-08-25 | 0.19 lb |
| Yellow Bullhead | 12.55 | 8–15 in 2025-08-25 | 0.91 lb |
| Largemouth Bass | 11.25 | 5–18 in 2025-08-25 | 0.99 lb |
| Spottail Shiner | 10.43 |
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.
Yellow Perch
Green Sunfish
Bluegill
Yellow Bullhead
From the 2025-08-25 survey
Lake Osakis (6,389 acres) is a nutrient-rich, highly productive basin located in both Douglas and Todd counties. Due to high nutrient levels, water quality can be seasonally impaired with periodic algal blooms and low water clarity ( In August 2025 a targeted fish survey was completed to gain current information on…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Osakis Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — OsakisFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Osakis (1077)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — OsakisFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — OsakisPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
73 ft
Average depth
20 ft
Surface area
6,389 acres
Shoreline
26.8 mi
Littoral zone
53%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
99 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,306 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Battle PointPublic
- Lake Osakis (South)Public
- Lake Osakis (Northwest)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 Osakis Lake
Compare lakeside cabins, hotels, and vacation rentals near Osakis Lake in Todd 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 Osakis Lake are listed below.
Top-rated places to stay near Osakis 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 trip? Cabins and lodging at Osakis Lake → · more Minnesota lake trips
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Fish Species
Click a species to see every lake where it is documented.
Fishing Osakis 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 Trend: Improving
Based on 4 years of monitoring (2022–2025).
Water clarity
Worsening3 years
Phosphorus
Improving-3.55 µg/L/yr4 years
Chlorophyll-a
Improving-0.63 µg/L/yr4 years
Ice season
Typical ice-out
Apr 19
Earliest Mar 8, 2024 · Latest May 14, 1950
Typical ice-in
Dec 1
Earliest Nov 27, 2007 · Latest Dec 9, 2016
Most recent ice-out
Apr 13
2025
431 observations · Minnesota PCA ice records
EPA Impairment Status
Osakis Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN77-0215-00 · Official waterbody report
Nearby Lakes in Todd County
Frequently asked questions about Osakis Lake
Where is Osakis Lake?
- Osakis Lake is a lake in Todd County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Osakis Lake?
- Osakis Lake in Todd County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10.5 ft visibility. Phosphorus: 75 µg/L. Chlorophyll-a (algae): 9.6 µg/L. Maximum depth: 73 ft. Surface area: 6389.35 acres.
Is Osakis Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Osakis Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Osakis Lake?
- Osakis Lake has a maximum depth of 73 feet and an average depth of 20 feet. The lake covers 6389.35 acres.
What fish are in Osakis Lake?
- Fish species found in Osakis Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Osakis Lake is located in Todd County, Minnesota.
What did the DNR fisheries survey find at Osakis Lake?
- Minnesota DNR's Targeted Survey on August 25, 2025 caught 6.83 walleye per gill net at Osakis Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Osakis Lake’s water-quality measurements separately, and the water-quality trend over 4 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does Osakis Lake thaw?
- Osakis Lake typically has ice-out around Apr 19. Ice typically forms around Dec 1. The open water season is approximately 226 days.
Are there boat ramps on Osakis Lake?
- Osakis Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Battle Point, Lake Osakis (South), Lake Osakis (Northwest). Public access is listed as yes.
Can I fish at Osakis Lake?
- Osakis Lake has 3 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 Osakis Lake across LakeQuality
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Fish species and best lakes in Todd County
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Where to stay at Minnesota's top lakes, each with its readings
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Where this data comes from
170 measurements from 3 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA170 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (3)
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
Ice data from Minnesota DNR Climate