Osakis Lake
Osakis Lake in Todd County, Minnesota has a water quality grade of D (Nutrient-rich). 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.
- Clarity
- 10.5 ft
- Max depth
- 73 ft
- Area
- 6,389 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 19
- Open water
- 226 days
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Osakis Lake →
Next lake in Todd County
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). Water quality is graded D based on 2 sampling years through 2025. 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 2 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. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyElevated nutrients
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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Good clarity, visible to about 10.5 ft. Phosphorus level: 75 µg/L. Chlorophyll-a: 9.6 µg/L. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.5 ft | Not graded |
| Phosphorus | 75 µg/L | Poor |
| Chlorophyll-a (Algae) | 9.6 µg/L | Fair |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay 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 grade measures nutrients and algae, not lodging — cabins and rentals around Osakis Lake are listed below.
Top-rated places to stay near Osakis 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 trip? Cabins and lodging at Osakis Lake → · more Minnesota lake trips
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 73 ft |
| Average Depth | 20 ft |
| Surface Area | 6,389 acres |
| Shoreline Length | 26.8 mi |
| Littoral Zone | 53% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Battle PointPublic
- Lake Osakis (Northwest)Public
Fish Species
Click a species to see every graded 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.
DNR Fisheries Survey Summary
17 surveys on file from MN DNR Fisheries. Most recent: 2022-08-15 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Perch | 23.45 | 0.14 lb |
| Green Sunfish | 22.70 | 0.14 lb |
| Bluegill | 18.20 | 0.18 lb |
| Largemouth Bass | 11.61 | 0.99 lb |
| Yellow Bass | 11.36 | 0.91 lb |
| Spottail Shiner | 10.43 | — |
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.
Yellow Perch
Green Sunfish
Bluegill
Largemouth Bass
From the 2022-08-15 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 (
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
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.105 m/yr | 3 |
| Phosphorus | ↑ Improving | -3.55 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.63 µg/L/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (431 observations).
Estimated open water season: 226 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-08 (2024) | 1950-05-14 (1950) |
| Ice-In | 2007-11-27 (2007) | 2016-12-09 (2016) |
Most recent ice-out: 2025-04-13
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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN77-0215-00 · Official waterbody report
County Ranking
Ranked #7 of 8 lakes in Todd County
Nearby Lakes With Higher Grades
Osakis Lake holds Grade D. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Todd County
Frequently asked questions about Osakis Lake
What is the water quality grade for Osakis Lake?
- Osakis Lake in Todd County, Minnesota has a water quality grade of D (Nutrient-rich). 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?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Osakis Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 9.6 µg/L. Always check local health department advisories before swimming.
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.
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 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Battle Point, Lake Osakis (Northwest). Public access is listed as yes.
Explore Osakis Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Todd County
Species activity outlook by water temperature and season
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High nutrients, frequent algae, reduced clarity
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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)
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