Cotton Lake
Becker County, Minnesota1,763 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Cotton Lake. Here is what has been measured.
- Impaired · Mercury
- 28 ft max depth
- Public access
- Limited data
Cotton Lake in Becker County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11.5 ft visibility. Maximum depth: 28 ft. Surface area: 1763.15 acres.
Minnesota DNR's Standard Survey on July 12, 2021 caught 5.33 walleye per gill net at Cotton Lake. DNR survey details →
Free interactive depth-contour map of Cotton Lake, reaching a maximum surveyed depth of 25 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Cotton Lake is a 1,763-acre lake in Becker County, Minnesota with a maximum depth of 28 feet. Overall water quality is improving over recent sampling years. The lake supports 15 documented fish species including black bullhead, black crappie, and bluegill. Public access is available.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-02. Methodology: how these readings are compared.
Cotton Lake covers about 1,800 acres in Becker County. The median ice-out date is April 23, which is when the open-water season begins. For a place on the water, look through cabin and lake-house rentals near Cotton Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Cotton Lake is good for
From access and monitoring records, not editorial picks.
- Clear water11.5 ft of visibility
- Fishing15 species recorded
- Ice seasonIce-out around Apr 23
- Big water1,763 acres
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Cotton Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Cotton 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 Cotton Lake
These are the measurements Minnesota PCA publishes for Cotton 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 11.5 ft. TSI 42.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 11.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 42 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Cotton Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Cotton Lake typically sits around 56°F at the surface in October. Summer average is about 72°F. Usually warmest in Aug (about 75°F) and coldest in Oct (about 56°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (56°F) to its warmest (75°F).
Typical surface water temperature by month, from 70 field readings (2016–2025) via the EPA Water Quality Portal. See the full Cotton Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Cotton Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (159,956 cells/mL) on May 9, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Minnesota DNR's Standard Survey on July 12, 2021 caught 5.33 walleye per gill net at Cotton Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Cotton Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2021-07-12 (Standard Survey).
12 surveys on file · most recent 2021-07-12 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluntnose Minnow | 175.70 | ||
| Bluegill | 31.13 | 2–9 in 2021-07-12 | 0.19 lb |
| Yellow Perch | 24.23 | 5–12 in 2021-07-12 | 0.35 lb |
| Yellow Bullhead | 6.21 | 4–15 in 2021-07-12 | 0.89 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.
Bluegill
Yellow Perch
Yellow Bullhead
From the 2021-07-12 survey
Cotton Lake is a 1,763-acre lake located in Becker county 12 miles east of the city of Detroit Lakes. The lake possesses a heavily developed shoreline and receives high recreational use and fishing pressure from the surrounding area, particularly during the open water season. The Shelly Island Wildlife Management Area…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Cotton Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — CottonFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Cotton (1221)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — CottonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — CottonPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
28 ft
Surface area
1,763 acres
Shoreline
10.9 mi
Littoral zone
44%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
6 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,437 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Cotton Lake
Compare lakeside cabins, hotels, and vacation rentals near Cotton Lake in Becker 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.
Top-rated places to stay near Cotton 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 Cotton Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Cotton Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Ice season
Typical ice-out
Apr 23
Earliest Mar 24, 2012 · Latest Nov 23, 2010
Typical ice-in
Nov 25
Earliest Nov 20, 2011 · Latest Dec 7, 2001
Most recent ice-out
Apr 17
2025
33 observations · Minnesota PCA ice records
EPA Impairment Status
Cotton 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: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN03-0286-00 · Official waterbody report
Nearby Lakes in Becker County
Frequently asked questions about Cotton Lake
Where is Cotton Lake?
- Cotton Lake is a lake in Becker County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Cotton Lake?
- Cotton Lake in Becker County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11.5 ft visibility. Maximum depth: 28 ft. Surface area: 1763.15 acres.
Is Cotton Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Cotton Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What is the water temperature of Cotton Lake?
- Cotton Lake typically sits around 56°F at the surface in October, from 70 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.
How deep is Cotton Lake?
- Cotton Lake has a maximum depth of 28 feet. The lake covers 1763.15 acres.
What fish are in Cotton Lake?
- Fish species found in Cotton Lake include black bullhead, black crappie, bluegill, brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Cotton Lake is located in Becker County, Minnesota.
What did the DNR fisheries survey find at Cotton Lake?
- Minnesota DNR's Standard Survey on July 12, 2021 caught 5.33 walleye per gill net at Cotton Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Cotton Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does Cotton Lake thaw?
- Cotton Lake typically has ice-out around Apr 23. Ice typically forms around Nov 25. The open water season is approximately 216 days.
Does Cotton Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Cotton Lake (clouds, ice, or an off-season gap). The most recent reading was high (159,956 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Can I fish at Cotton Lake?
- Public access to Cotton Lake is listed as yes on the lake record. 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 Cotton Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Becker County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Detroit Lakes Area area
Top lakes and where to stay in the Park Rapids Area area
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Red River of the North Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
Other Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
83 measurements from 2 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
MNPCA83 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (2)
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
Ice data from Minnesota DNR Climate