Cottonwood Lake
Cottonwood Lake in Cottonwood County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 2.1 ft visibility. Phosphorus: 60 µg/L. Chlorophyll-a (algae): 18.2 µg/L. Maximum depth: 10 ft. Surface area: 154.97 acres.
- Clarity
- 2.1 ft
- Typical in August
- 76°F
- Max depth
- 10 ft
- Area
- 155 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Cottonwood Lake →
Next lake in Cottonwood County
Cottonwood Lake is a 155-acre productive, nutrient-rich eutrophic lake in Cottonwood County, Minnesota with a maximum depth of 10 feet (8-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 15 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 3 public boat landings. Compared to the 2 other monitored lakes in Cottonwood County, Cottonwood Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-03. 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.
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)
Very murky, less than 2.1 ft of visibility. Phosphorus level: 60 µg/L. Chlorophyll-a: 18.2 µg/L. Trophic State Index: 63.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.1 ft | Not graded |
| Phosphorus | 60 µg/L | Poor |
| Chlorophyll-a (Algae) | 18.2 µg/L | Fair |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Cottonwood Lake
Compare lakeside cabins, hotels, and vacation rentals near Cottonwood Lake in Cottonwood 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 Cottonwood Lake are listed below.
Top-rated places to stay near Cottonwood Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Cottonwood Lake typically sits around 76°F at the surface in August. Summer average is about 77°F. Usually warmest in Jul (about 82°F) and coldest in Jun (about 73°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 20 field readings (2022–2025) via the EPA Water Quality Portal. See the full Cottonwood Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 10 ft |
| Average Depth | 8 ft |
| Surface Area | 155 acres |
| Shoreline Length | 3.5 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Dam SitePublic
- Clear LakePublic
- Cottonwood LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Cottonwood Lake
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2024-08-19 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 92.97 | 0.15 lb |
| SUN | 72.76 | — |
| Black Crappie | 11.89 | 0.25 lb |
| Yellow Perch | 11.43 | 0.15 lb |
| Bluegill | 7.26 | 0.23 lb |
| Largemouth Bass | 5.54 | 2.68 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
Black Crappie
Yellow Perch
Bluegill
From the 2024-08-19 survey
Cottonwood Lake is a small shallow lake, 155 acres and 11 feet max depth, located in the City of Windom in Cottonwood County. While there are many concerns about water quality and water quantity in Cottonwood Lake, the lake remains resilient and has some decent fishing at times. Cottonwood Lake is managed primarily…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Cottonwood Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — CottonwoodFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — CottonwoodFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — CottonwoodPublic 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 | ↓ Declining | -0.193 m/yr | 2 |
| Phosphorus | ↑ Improving | -9.5 µg/L/yr | 2 |
| Chlorophyll-a | ↑ Improving | -1.43 µg/L/yr | 2 |
EPA Impairment Status
Cottonwood Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN17-0022-00 · Official waterbody report
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Cottonwood Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Windom WwtpWindom · 1.2 mi away · NPDES MN0022217MajorRecent violation
- Pm WindomWindom · 2.1 mi away · NPDES MN0067482
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #2 of 3 lakes in Cottonwood County
Nearby Lakes With Higher Grades
Cottonwood Lake holds Grade D. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Cottonwood County
Frequently asked questions about Cottonwood Lake
What is the water quality grade for Cottonwood Lake?
- Cottonwood Lake in Cottonwood County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 2.1 ft visibility. Phosphorus: 60 µg/L. Chlorophyll-a (algae): 18.2 µg/L. Maximum depth: 10 ft. Surface area: 154.97 acres.
Is Cottonwood 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. Cottonwood Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 18.2 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Cottonwood Lake?
- Cottonwood Lake typically sits around 76°F at the surface in August, from 20 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.
How deep is Cottonwood Lake?
- Cottonwood Lake has a maximum depth of 10 feet and an average depth of 8 feet. The lake covers 154.97 acres.
What fish are in Cottonwood Lake?
- Fish species found in Cottonwood Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, channel catfish, common carp, largemouth bass, northern pike, orangespotted sunfish, pumpkinseed, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Cottonwood Lake is located in Cottonwood County, Minnesota.
Are there boat ramps on Cottonwood Lake?
- Cottonwood Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Dam Site, Clear Lake, Cottonwood Lake. Public access is listed as yes.
Explore Cottonwood Lake across LakeGrade
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Fish species and best lakes in Cottonwood 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
16 measurements from 1 monitoring station, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA16 samples · 2022–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2120 B ~ Color in Water by Visual Comparison
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory