Cowdry Lake
Cowdry Lake in Douglas County, Minnesota has a water quality grade of A (Excellent). Water clarity: 17.1 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Maximum depth: 52 ft. Surface area: 242.54 acres.
- Clarity
- 17.1 ft
- Typical in August
- 75°F
- Max depth
- 52 ft
- Area
- 243 acres
- Type
- Oligotrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 19
- Open water
- 231 days
Next lake in Douglas County
Cowdry Lake is a 243-acre cold, clear oligotrophic lake in Douglas County, Minnesota with a maximum depth of 52 feet (25-foot average). Water quality is graded A based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 19 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 36 other monitored lakes in Douglas County, Cowdry Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Crystal clear, you can see 17.1 ft down. Phosphorus level: 15 µg/L. Chlorophyll-a: 2.4 µg/L. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 17.1 ft | Not graded |
| Phosphorus | 15 µg/L | Good |
| Chlorophyll-a (Algae) | 2.4 µg/L | Good |
| Trophic State Index (TSI) | 40 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Cowdry Lake
Compare lakeside cabins, hotels, and vacation rentals near Cowdry Lake in Douglas 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.
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Water Temperature
Cowdry Lake typically sits around 75°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 75°F) and coldest in Jun (about 69°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 45 field readings (2010–2025) via the EPA Water Quality Portal. See the full Cowdry Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 52 ft |
| Average Depth | 25 ft |
| Surface Area | 243 acres |
| Shoreline Length | 3.1 mi |
| Littoral Zone | 35% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Cowdry LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Cowdry 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
10 surveys on file from MN DNR Fisheries. Most recent: 2019-07-29 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| CNM | 40.58 | — |
| Largemouth Bass | 29.96 | 0.79 lb |
| Bluntnose Minnow | 27.02 | — |
| Bluegill | 21.65 | 0.13 lb |
| Yellow Bass | 8.49 | 0.66 lb |
| Black Bullhead | 7.13 | 0.76 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.
Largemouth Bass
Bluegill
Yellow Bass
Black Bullhead
From the 2019-07-29 survey
This nearshore survey was conducted during summer 2019 to assess populations of non-game species and small game fish using backpack electrofishing and seining. Backpack electrofishing and/or seining were conducted at 10 stations, representing a variety of habitat types, along the shoreline of Lake Cowdry. The survey…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Cowdry Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — CowdryFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — CowdryFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — CowdryPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.19 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.57 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | +0.03 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (26 observations).
Estimated open water season: 231 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-12 (2024) | 2013-05-11 (2013) |
| Ice-In | 2019-11-12 (2019) | 2015-12-19 (2015) |
Most recent ice-out: 2024-03-12
EPA Impairment Status
Cowdry Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN21-0080-00 · Official waterbody report · Matched by proximity (2.51 km)
County Ranking
Ranked #5 of 37 lakes in Douglas County
Nearby Lakes in Douglas County
Frequently asked questions about Cowdry Lake
What is the water quality grade for Cowdry Lake?
- Cowdry Lake in Douglas County, Minnesota has a water quality grade of A (Excellent). Water clarity: 17.1 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 2.4 µg/L. Maximum depth: 52 ft. Surface area: 242.54 acres.
Is Cowdry Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Cowdry Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.4 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Cowdry Lake?
- Cowdry Lake typically sits around 75°F at the surface in August, from 45 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Cowdry Lake?
- Cowdry Lake has a maximum depth of 52 feet and an average depth of 25 feet. The lake covers 242.54 acres.
What fish are in Cowdry Lake?
- Fish species found in Cowdry Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, shorthead redhorse, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Cowdry Lake is located in Douglas County, Minnesota.
When does Cowdry Lake thaw?
- Cowdry Lake typically has ice-out around Apr 19. Ice typically forms around Dec 6. The open water season is approximately 231 days.
Are there boat ramps on Cowdry Lake?
- Cowdry Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Cowdry Lake. Public access is listed as yes.
Explore Cowdry Lake across LakeGrade
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Where this data comes from
142 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
MNPCA142 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (2)
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