Agnes Lake
Douglas County, Minnesota137 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Agnes Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- zebra mussel
- 31 ft max depth
- Public access
Agnes Lake in Douglas County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.4 ft visibility. Phosphorus: 37.5 µg/L. Chlorophyll-a (algae): 15 µg/L. Maximum depth: 31 ft. Surface area: 137.46 acres.
Minnesota DNR's Standard Survey on June 5, 2023 caught 5.67 walleye per gill net at Agnes Lake. DNR survey details →
Agnes Lake is a 137-acre productive, nutrient-rich eutrophic lake in Douglas County, Minnesota with a maximum depth of 31 feet (12-foot average). Overall water quality is improving over recent sampling years. The lake supports 12 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, Agnes Lake ranks #31 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-06. Methodology: how these readings are compared.
What Agnes Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing12 species recorded
- Deep water31 ft surveyed max depth
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Agnes Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), salinity / chlorides. Check local advisories before you swim.
Whether Agnes 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 Agnes Lake
These are the measurements Minnesota PCA publishes for Agnes Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5.4 ft. Phosphorus 37.5 µg/L. Chlorophyll-a 15 µg/L. TSI 55.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 37.5µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 15µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 55 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Agnes Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Agnes Lake typically sits around 59°F at the surface in October. Summer average is about 74°F. Usually warmest in Jul (about 76°F) and coldest in Oct (about 59°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (59°F) to its warmest (76°F).
Typical surface water temperature by month, from 67 field readings (2010–2025) via the EPA Water Quality Portal. See the full Agnes Lake water temperature breakdown →
Minnesota DNR's Standard Survey on June 5, 2023 caught 5.67 walleye per gill net at Agnes Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Agnes Lake’s water-quality measurements separately, and the water-quality trend over 4 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
11 surveys on file from MN DNR Fisheries. Most recent: 2023-06-05 (Standard Survey).
11 surveys on file · most recent 2023-06-05 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 148.53 | 7–11 in 2017-06-05 | 0.39 lb |
| Largemouth Bass | 28.56 | 5–18 in 2023-06-05 | 1.17 lb |
| Yellow Perch | 27.78 | 5–9 in 2023-06-05 | 0.17 lb |
| Common Carp | 20.41 | 24 in 2023-06-05 | 2.76 lb |
| Fathead Minnow | 16.89 | ||
| Black Crappie | 10.32 | 4–10 in 2023-06-05 | 0.25 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.
Black Bullhead
Largemouth Bass
Yellow Perch
Common Carp
From the 2023-06-05 survey
Lake Agnes is a small (137 acres), productive basin located within the Long Prairie River watershed. Mean and maximum depths are 12 and 31 feet, respectively. Lake Agnes, along with lakes Henry and Winona, comprise a chain of lakes within the city limits of Alexandria. Lakes Agnes and Henry are broadly connected with…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Agnes Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — AgnesFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — AgnesFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — AgnesPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
31 ft
Average depth
12 ft
Surface area
137 acres
Shoreline
1.7 mi
Littoral zone
45%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Recreation & Access
- Lake AgnesPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Agnes Lake
Compare lakeside cabins, hotels, and vacation rentals near Agnes 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Agnes Lake are listed below.
Top-rated places to stay near Agnes 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 →
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Fish Species
Click a species to see every lake where it is documented.
Fishing Agnes 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.
Water Quality Trend: Improving
Based on 4 years of monitoring (2022–2025).
Water clarity
Improving4 years
Phosphorus
Improving-3.5 µg/L/yr4 years
Chlorophyll-a
Improving-1.46 µg/L/yr4 years
EPA Impairment Status
Agnes Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN21-0053-00 · Official waterbody report
Nearby Lakes in Douglas County
Frequently asked questions about Agnes Lake
Where is Agnes Lake?
- Agnes Lake is a lake in Douglas County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Agnes Lake?
- Agnes Lake in Douglas County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.4 ft visibility. Phosphorus: 37.5 µg/L. Chlorophyll-a (algae): 15 µg/L. Maximum depth: 31 ft. Surface area: 137.46 acres.
Is Agnes Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Agnes Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), salinity / chlorides. Check local advisories before you swim.
What is the water temperature of Agnes Lake?
- Agnes Lake typically sits around 59°F at the surface in October, from 67 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Agnes Lake?
- Agnes Lake has a maximum depth of 31 feet and an average depth of 12 feet. The lake covers 137.46 acres.
What fish are in Agnes Lake?
- Fish species found in Agnes Lake include black bullhead, black crappie, bluegill, brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, walleye, white sucker, yellow perch. Agnes Lake is located in Douglas County, Minnesota.
What did the DNR fisheries survey find at Agnes Lake?
- Minnesota DNR's Standard Survey on June 5, 2023 caught 5.67 walleye per gill net at Agnes Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Agnes Lake’s water-quality measurements separately, and the water-quality trend over 4 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Agnes Lake?
- Agnes Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lake Agnes. Public access is listed as yes.
Can I fish at Agnes Lake?
- Agnes Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. 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 Agnes Lake across LakeQuality
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Where this data comes from
155 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
MNPCA155 samples · 2022–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (1)
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 details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory