Ann Lake
Wright County, Minnesota375 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Ann Lake. Here is what has been measured.
- Eutrophic
- Impaired · Impaired biota (cause unknown)
- 19 ft max depth
- Public access
Ann Lake in Wright County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4 ft visibility. Phosphorus: 267 µg/L. Chlorophyll-a (algae): 34.7 µg/L. Maximum depth: 18.5 ft. Surface area: 375.4 acres.
Minnesota DNR's Targeted Survey on July 23, 2025 caught 3.53 largemouth bass per hour of electrofishing at Ann Lake. Length samples in the latest survey that recorded them ran 4–19 inches. DNR survey details →
Ann Lake is a 375-acre productive, nutrient-rich eutrophic lake in Wright County, Minnesota with a maximum depth of 19 feet (10-foot average). Overall water quality is improving over recent sampling years. The lake supports 16 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 1 public boat landing. Compared to the 50 other monitored lakes in Wright County, Ann Lake ranks #35 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-23. Methodology: how these readings are compared.
What Ann Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing16 species recorded
- Ice seasonIce-out around Apr 8
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. Ann Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Ann 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 Ann Lake
These are the measurements Minnesota PCA publishes for Ann 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 4 ft. Phosphorus 267 µg/L. Chlorophyll-a 34.7 µg/L. TSI 69.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 267µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 34.7µg/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. | 69 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Ann Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Ann Lake typically sits around 58°F at the surface in October. Summer average is about 73°F. Usually warmest in Jul (about 75°F) and coldest in Nov (about 39°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (39°F) to its warmest (75°F).
Typical surface water temperature by month, from 350 field readings (2010–2023) via the EPA Water Quality Portal. See the full Ann Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Ann Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (524,807 cells/mL) on July 18, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Minnesota DNR's Targeted Survey on July 23, 2025 caught 3.53 largemouth bass per hour of electrofishing at Ann Lake. Length samples in the latest survey that recorded them ran 4–19 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Ann Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2025-09-24 (Targeted Survey).
12 surveys on file · most recent 2025-09-24 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 86.19 | 5–20 in 2016-08-01 | 0.32 lb |
| Bluegill | 18.36 | 3–9 in 2016-08-01 | 0.17 lb |
| Yellow Perch | 17.95 | 5–9 in 2016-08-01 | 0.19 lb |
| Green Sunfish | 16.80 | 4 in 2016-08-01 | 0.05 lb |
| Black Crappie | 16.52 | 4–13 in 2016-08-01 | 0.25 lb |
| Largemouth Bass | 12.27 | 4–19 in 2016-08-01 | 0.79 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
Bluegill
Yellow Perch
Green Sunfish
From the 2025-09-24 survey
Ann Lake is a popular fishing lake located three miles south of Howard Lake in southern Wright County. The 386-acre lake has a maximum depth of 18.5 feet and a ten-year average water clarity of 3.3 feet. There is one public access located on the west side. The Walleye fishery of Ann Lake has been managed by stocking…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Ann Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — AnnFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — AnnFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — AnnPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
18.5 ft
Average depth
10.1 ft
Surface area
375 acres
Shoreline
3.6 mi
Littoral zone
79%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
5 sq mi
HydroLAKES / HydroSHEDS
Elevation
978 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Ann LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Ann Lake
Compare lakeside cabins, hotels, and vacation rentals near Ann Lake in Wright 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 Ann Lake are listed below.
Top-rated places to stay near Ann 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 Ann Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Worsening+41.5 µg/L/yr6 years
Chlorophyll-a
Improving-10.74 µg/L/yr6 years
Ice season
Typical ice-out
Apr 8
Earliest Mar 13, 2016 · Latest Apr 23, 2008
Most recent ice-out
Mar 13
2016
4 observations · Minnesota PCA ice records
EPA Impairment Status
Ann 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 MN86-0190-00 · Official waterbody report
Nearby Lakes in Wright County
Frequently asked questions about Ann Lake
Where is Ann Lake?
- Ann Lake is a lake in Wright County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Ann Lake?
- Ann Lake in Wright County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4 ft visibility. Phosphorus: 267 µg/L. Chlorophyll-a (algae): 34.7 µg/L. Maximum depth: 18.5 ft. Surface area: 375.4 acres.
Is Ann Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Ann Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Ann Lake?
- Ann Lake typically sits around 58°F at the surface in October, from 350 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
How deep is Ann Lake?
- Ann Lake has a maximum depth of 18.5 feet and an average depth of 10.1 feet. The lake covers 375.4 acres.
What fish are in Ann Lake?
- Fish species found in Ann Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow bullhead, yellow perch. Ann Lake is located in Wright County, Minnesota.
What did the DNR fisheries survey find at Ann Lake?
- Minnesota DNR's Targeted Survey on July 23, 2025 caught 3.53 largemouth bass per hour of electrofishing at Ann Lake. Length samples in the latest survey that recorded them ran 4–19 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Ann Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does Ann Lake thaw?
- Ann Lake typically has ice-out around Apr 8.
Does Ann Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Ann Lake (clouds, ice, or an off-season gap). The most recent reading was high (524,807 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Ann Lake?
- Ann Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Ann Lake. Public access is listed as yes.
Can I fish at Ann Lake?
- Ann 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 Ann Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Wright County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Crow River Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
State Parks Near Ann Lake
Other Lakes in Minnesota
Eutrophic Lakes in Minnesota
Where this data comes from
165 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA165 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 (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 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