Agnes Lake
Agnes Lake in Douglas County, Minnesota has a water quality grade of D (Nutrient-rich). 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.
- Clarity
- 5.4 ft
- Typical in August
- 74°F
- Max depth
- 31 ft
- Area
- 137 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Agnes Lake →
Next lake in Douglas County
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). Water quality is graded D based on 2 sampling years through 2025. 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. Grade methodology: LakeGrade methodology.
Watch Agnes Lake water quality
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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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Murky, only visible to about 5.4 ft. Phosphorus level: 37.5 µg/L. Chlorophyll-a: 15 µg/L. Trophic State Index: 55.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.4 ft | Not graded |
| Phosphorus | 37.5 µg/L | Fair |
| Chlorophyll-a (Algae) | 15 µg/L | Poor |
| Trophic State Index (TSI) | 55 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay 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 grade measures nutrients and algae, not lodging — cabins and rentals around Agnes Lake are listed below.
Top-rated places to stay near Agnes Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Agnes Lake typically sits around 74°F at the surface in August. 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.
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 →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 31 ft |
| Average Depth | 12 ft |
| Surface Area | 137 acres |
| Shoreline Length | 1.7 mi |
| Littoral Zone | 45% |
| Public Access | Yes |
Recreation & Access
- Lake AgnesPublic
Fish Species
Click a species to see every graded 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.
DNR Fisheries Survey Summary
11 surveys on file from MN DNR Fisheries. Most recent: 2023-06-05 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 148.53 | 0.39 lb |
| Largemouth Bass | 28.56 | 1.17 lb |
| Yellow Perch | 27.78 | 0.17 lb |
| Common Carp | 20.41 | 2.76 lb |
| Fathead Minnow | 16.89 | — |
| Black Crappie | 10.32 | 0.25 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
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
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.11 m/yr | 4 |
| Phosphorus | ↑ Improving | -3.5 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -1.46 µg/L/yr | 4 |
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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN21-0053-00 · Official waterbody report
County Ranking
Ranked #31 of 37 lakes in Douglas County
Nearby Lakes With Higher Grades
Agnes Lake holds Grade D. 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 Douglas County
Frequently asked questions about Agnes Lake
What is the water quality grade for Agnes Lake?
- Agnes Lake in Douglas County, Minnesota has a water quality grade of D (Nutrient-rich). 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?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Agnes Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 15 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Agnes Lake?
- Agnes Lake typically sits around 74°F at the surface in August, 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.
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.
Explore Agnes Lake across LakeGrade
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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)
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