Sleepy Eye Lake
Sleepy Eye Lake in Brown County, Minnesota has a water quality grade of C (Fair). Water clarity: 3.3 ft visibility. Phosphorus: 39.5 µg/L. Chlorophyll-a (algae): 18.7 µg/L. Maximum depth: 21 ft. Surface area: 240.82 acres.
- Clarity
- 3.3 ft
- Typical in August
- 76°F
- Max depth
- 21 ft
- Area
- 241 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Mar 27
- Open water
- 243 days
Next lake in Brown County
Sleepy Eye Lake is a 241-acre productive, nutrient-rich eutrophic lake in Brown County, Minnesota with a maximum depth of 21 feet (7-foot average). Water quality is graded C based on 2 sampling years through 2023. Overall water quality is declining over recent sampling years. The lake supports 10 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 3 other monitored lakes in Brown County, Sleepy Eye Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-10-11. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyAlgae risk
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.
Swim with caution, moderate algae may be present
Water Quality Grade: C (Fair)
Very murky, less than 3.3 ft of visibility. Phosphorus level: 39.5 µg/L. Chlorophyll-a: 18.7 µg/L. Trophic State Index: 59.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.3 ft | Not graded |
| Phosphorus | 39.5 µg/L | Fair |
| Chlorophyll-a (Algae) | 18.7 µg/L | Fair |
| Trophic State Index (TSI) | 59 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Sleepy Eye Lake
Compare lakeside cabins, hotels, and vacation rentals near Sleepy Eye Lake in Brown 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
Sleepy Eye Lake typically sits around 76°F at the surface in August. Summer average is about 79°F. Usually warmest in Jul (about 81°F) and coldest in Oct (about 52°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 96 field readings (2017–2023) via the EPA Water Quality Portal. See the full Sleepy Eye Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 21 ft |
| Average Depth | 7 ft |
| Surface Area | 241 acres |
| Shoreline Length | 4.3 mi |
| Littoral Zone | 84% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Sleepy Eye Lake #1Public
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Sleepy Eye Lake
DNR Fisheries Survey Summary
18 surveys on file from MN DNR Fisheries. Most recent: 2021-08-16 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 116.05 | 0.47 lb |
| Bluegill | 31.13 | 0.16 lb |
| White Crappie | 26.64 | 0.32 lb |
| Yellow Perch | 20.59 | 0.15 lb |
| Black Crappie | 14.73 | 0.24 lb |
| Largemouth Bass | 8.97 | 1.53 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
Bluegill
Yellow Perch
Black Crappie
From the 2021-08-16 survey
Sleepy Eye is a smaller sized lake (240 acres) located adjacent to the City of Sleepy Eye in Brown County. A large city-owned access with a double cement boat ramp is located on the north shore within the Sleepy Eye Sportsmen's Park. Sleepy Eye Lake has 4 miles of shoreline and a maximum depth of 21 feet. The…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Sleepy Eye Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Sleepy EyeFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — Sleepy EyeFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Sleepy EyePublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.151 m/yr | 4 |
| Phosphorus | ↓ Declining | +13.95 µg/L/yr | 4 |
| Chlorophyll-a | ↓ Declining | +7.3 µg/L/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (28 observations).
Estimated open water season: 243 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2017-03-06 (2017) | 2013-04-18 (2013) |
| Ice-In | 1991-11-05 (1991) | 2015-12-18 (2015) |
Most recent ice-out: 2019-04-08
Reservoir Info (USACE NID)
Sleepy Eye Lake is a man-made reservoir impounded by the Sleepy Eye Control (completed 1949), built primarily for recreation on the County Ditch 5; gravity-type dam, 8 ft tall and 35 ft long.
- Surface area
- 227 ac
- Normal storage
- 2,300 ac-ft
- Max storage
- 2,975 ac-ft
- Drainage area
- 1.5 sq mi
- Hazard class
- Low
- Owner
- City of Sleepy Eye
Source: USACE National Inventory of Dams, NID ID MN00754 · Operator website · Matched by proximity (0.36 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Sleepy Eye Lake under Clean Water Act (NPDES) discharge permits.
- Edward Berkner FarmSleepy Eye · 4.2 mi away · NPDES MN0071277
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 #1 of 4 lakes in Brown County
Nearby Lakes in Brown County
Frequently asked questions about Sleepy Eye Lake
What is the water quality grade for Sleepy Eye Lake?
- Sleepy Eye Lake in Brown County, Minnesota has a water quality grade of C (Fair). Water clarity: 3.3 ft visibility. Phosphorus: 39.5 µg/L. Chlorophyll-a (algae): 18.7 µg/L. Maximum depth: 21 ft. Surface area: 240.82 acres.
Is Sleepy Eye Lake safe to swim in?
- Swim with caution, moderate algae may be present. Sleepy Eye Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 18.7 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Sleepy Eye Lake?
- Sleepy Eye Lake typically sits around 76°F at the surface in August, from 96 EPA Water Quality Portal field readings (2017–2023). That is a typical value for the month, not a live reading.
How deep is Sleepy Eye Lake?
- Sleepy Eye Lake has a maximum depth of 21 feet and an average depth of 7 feet. The lake covers 240.82 acres.
What fish are in Sleepy Eye Lake?
- Fish species found in Sleepy Eye Lake include black bullhead, black crappie, bluegill, channel catfish, common carp, hybrid sunfish, largemouth bass, northern pike, walleye, yellow perch. Sleepy Eye Lake is located in Brown County, Minnesota.
When does Sleepy Eye Lake thaw?
- Sleepy Eye Lake typically has ice-out around Mar 27. Ice typically forms around Nov 25. The open water season is approximately 243 days.
Are there boat ramps on Sleepy Eye Lake?
- Sleepy Eye Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Sleepy Eye Lake #1. Public access is listed as yes.
Explore Sleepy Eye Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
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Fish species and best lakes in Brown County
Species activity outlook by water temperature and season
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High nutrients, frequent algae, reduced clarity
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State Parks Near Sleepy Eye Lake
Other Grade C Lakes in Minnesota
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Where this data comes from
195 measurements from 1 monitoring station, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA195 samples · 2020–2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity, Nephelometric Method
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
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
Ice data from Minnesota DNR Climate