Ann Lake
Ann Lake in Wright County, Minnesota has a water quality grade of F (Algae-prone). 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.
- Clarity
- 4 ft
- Typical in August
- 73°F
- Max depth
- 18.5 ft
- Area
- 375 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 8
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Ann Lake →
Next lake in Wright County
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). Water quality is graded F based on 2 sampling years through 2025. 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 2 public boat landings. 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. 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.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
Murky, only visible to about 4 ft. Phosphorus level: 267 µg/L. Chlorophyll-a: 34.7 µg/L. Trophic State Index: 69.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4 ft | Not graded |
| Phosphorus | 267 µg/L | Poor |
| Chlorophyll-a (Algae) | 34.7 µg/L | Poor |
| Trophic State Index (TSI) | 69 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay 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 grade measures nutrients and algae, not lodging — cabins and rentals around Ann Lake are listed below.
Top-rated places to stay near Ann Lake
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 →
Water Temperature
Ann Lake typically sits around 73°F at the surface in August. 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.
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 ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 18.5 ft |
| Average Depth | 10.1 ft |
| Surface Area | 375 acres |
| Shoreline Length | 3.6 mi |
| Littoral Zone | 79% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Ann LakePublic
- Dutch LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Ann Lake
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2025-09-24 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 86.19 | 0.32 lb |
| Bluegill | 18.36 | 0.17 lb |
| Yellow Perch | 17.95 | 0.19 lb |
| Green Sunfish | 16.80 | 0.05 lb |
| Black Crappie | 16.52 | 0.25 lb |
| Largemouth Bass | 12.27 | 0.79 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
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
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.28 m/yr | 6 |
| Phosphorus | ↓ Declining | +41.5 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -10.74 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (4 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2016-03-13 (2016) | 2008-04-23 (2008) |
| Ice-In | 2008-11-20 (2008) | 2008-11-20 (2008) |
Most recent ice-out: 2016-03-13
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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN86-0190-00 · Official waterbody report
County Ranking
Ranked #35 of 51 lakes in Wright County
Nearby Lakes With Higher Grades
Ann Lake holds Grade F. 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 Wright County
Frequently asked questions about Ann Lake
What is the water quality grade for Ann Lake?
- Ann Lake in Wright County, Minnesota has a water quality grade of F (Algae-prone). 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?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Ann Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 34.7 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Ann Lake?
- Ann Lake typically sits around 73°F at the surface in August, 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.
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 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Ann Lake, Dutch Lake. Public access is listed as yes.
Explore Ann Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded 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 grade
Lakes in the Crow River Watershed, ranked by water quality
High nutrients, frequent algae, reduced clarity
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Ann Lake
Other Grade F 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)
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