Upper Cormorant Lake
Upper Cormorant Lake in Becker County, Minnesota has a water quality grade of C (Fair). Water clarity: 8 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 9.9 µg/L. Maximum depth: 29 ft. Surface area: 974 acres.
- Clarity
- 8 ft
- Typical in August
- 72°F
- Max depth
- 29 ft
- Area
- 974 acres
- Type
- Eutrophic
- Trend
- → Stable
- Public access
- Yes
- Ice-out
- Apr 26
- Open water
- 211 days
Next lake in Becker County
Free interactive depth-contour map of Upper Cormorant Lake, reaching a maximum surveyed depth of 25 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Upper Cormorant Lake is a 974-acre productive, nutrient-rich eutrophic lake in Becker County, Minnesota with a maximum depth of 29 feet. Water quality is graded C based on 2 sampling years through 2025. Water clarity is declining over recent sampling years. The lake supports 13 documented fish species including black crappie, bluegill, and brown bullhead. Public access is available with 1 public boat landing. Compared to the 83 other monitored lakes in Becker County, Upper Cormorant Lake ranks #59 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-16. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyModerate
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Moderate clarity, visible to about 8 ft. Phosphorus level: 30 µg/L. Chlorophyll-a: 9.9 µg/L. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8 ft | Not graded |
| Phosphorus | 30 µg/L | Fair |
| Chlorophyll-a (Algae) | 9.9 µg/L | Fair |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Upper Cormorant Lake
Compare lakeside cabins, hotels, and vacation rentals near Upper Cormorant 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.
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Water Temperature
Upper Cormorant Lake typically sits around 72°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 78°F) and coldest in May (about 60°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 34 field readings (2011–2025) via the EPA Water Quality Portal. See the full Upper Cormorant Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Upper Cormorant Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (59,156 cells/mL) on November 29, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 29 ft |
| Surface Area | 974 acres |
| Shoreline Length | 12.9 mi |
| Littoral Zone | 48% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Upper Cormorant LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Upper Cormorant 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
13 surveys on file from MN DNR Fisheries. Most recent: 2025-08-11 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Largemouth Bass | 40.62 | 1.01 lb |
| Bluegill | 30.74 | 0.19 lb |
| Bluntnose Minnow | 17.39 | — |
| Green Sunfish | 11.78 | 0.16 lb |
| Yellow Bass | 11.53 | 0.61 lb |
| CNM | 9.62 | — |
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
Green Sunfish
Yellow Bass
From the 2025-08-11 survey
Upper Cormorant Lake is an 856-acre, class 25 lake located in southwestern Becker County. It consists of a main basin and a long, narrow, northern arm with several shallow bays. Two narrow channels, not navigable in low water years, provide access to Rossman and Nelson Lakes to the east and eventually connect to…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Upper Cormorant Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Upper CormorantFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — Upper CormorantFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Upper CormorantPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.056 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.9 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | -0.05 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (20 observations).
Estimated open water season: 211 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2016-03-29 (2016) | 2022-05-06 (2022) |
| Ice-In | 1995-11-10 (1995) | 2017-12-07 (2017) |
Most recent ice-out: 2023-05-05
EPA Impairment Status
Upper Cormorant 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 MN03-0588-00 · Official waterbody report
County Ranking
Ranked #59 of 84 lakes in Becker County
Nearby Lakes With Higher Grades
Upper Cormorant Lake holds Grade C. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Becker County
Frequently asked questions about Upper Cormorant Lake
What is the water quality grade for Upper Cormorant Lake?
- Upper Cormorant Lake in Becker County, Minnesota has a water quality grade of C (Fair). Water clarity: 8 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 9.9 µg/L. Maximum depth: 29 ft. Surface area: 974 acres.
Is Upper Cormorant Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Upper Cormorant Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 9.9 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Upper Cormorant Lake?
- Upper Cormorant Lake typically sits around 72°F at the surface in August, from 34 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Upper Cormorant Lake?
- Upper Cormorant Lake has a maximum depth of 29 feet. The lake covers 974 acres.
What fish are in Upper Cormorant Lake?
- Fish species found in Upper Cormorant Lake include black crappie, bluegill, brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow bullhead, yellow perch. Upper Cormorant Lake is located in Becker County, Minnesota.
When does Upper Cormorant Lake thaw?
- Upper Cormorant Lake typically has ice-out around Apr 26. Ice typically forms around Nov 23. The open water season is approximately 211 days.
Does Upper Cormorant Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Upper Cormorant Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (59,156 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Upper Cormorant Lake?
- Upper Cormorant Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Upper Cormorant Lake. Public access is listed as yes.
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Where this data comes from
134 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
MNPCA134 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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