Mary Lake
Wright County, Minnesota196 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Mary Lake. Here is what has been measured.
- Impaired · Impaired biota (cause unknown)
- Eurasian watermilfoil
- 102 ft max depth
- Public access
- Limited data
Mary Lake in Wright County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5 ft visibility. Maximum depth: 102 ft. Surface area: 196.03 acres.
Minnesota DNR's Standard Survey on August 14, 2017 caught 2.00 walleye per gill net at Mary Lake. DNR survey details →
Mary Lake is a 196-acre lake in Wright County, Minnesota with a maximum depth of 102 feet (35-foot average). Overall water quality is declining over recent sampling years. The lake supports 13 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-27. Methodology: how these readings are compared.
What Mary Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing13 species recorded
- Ice seasonIce-out around Apr 4
- Deep water102 ft surveyed max depth
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Mary Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury. Check local advisories before you swim.
Whether Mary 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 Mary Lake
These are the measurements Minnesota PCA publishes for Mary 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 ft. TSI 54.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 54 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Mary Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Mary Lake typically sits around 57°F at the surface in October. Summer average is about 61°F. Usually warmest in Aug (about 64°F) and coldest in Oct (about 57°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (57°F) to its warmest (64°F).
Typical surface water temperature by month, from 134 field readings (2022–2025) via the EPA Water Quality Portal.
Minnesota DNR's Standard Survey on August 14, 2017 caught 2.00 walleye per gill net at Mary Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Mary Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
6 surveys on file from MN DNR Fisheries. Most recent: 2017-08-14 (Standard Survey).
6 surveys on file · most recent 2017-08-14 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 26.55 | 2–8 in 2017-08-14 | 0.14 lb |
| Largemouth Bass | 12.03 | 2–21 in 2017-08-14 | 1.07 lb |
| Yellow Perch | 11.10 | 6 in 2017-08-14 | 0.09 lb |
| Green Sunfish | 10.18 | 3–4 in 2017-08-14 | 0.04 lb |
| Black Bullhead | 8.27 | 11–13 in 2017-08-14 | 0.55 lb |
| Black Crappie | 5.19 | 4–10 in 2017-08-14 | 0.22 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.
Bluegill
Largemouth Bass
Yellow Perch
Green Sunfish
From the 2017-08-14 survey
Mary Lake is a 209 acre general development lake located two miles north of Maple Lake in central Wright County. A public access is located on the northwest side of the lake with room for 4 - 6 truck/trailer rigs. Mary Lake has a maximum depth of 102 feet and water clarity is fair with an average summer Secchi reading…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Mary Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MaryFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Mary (2016)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — MaryFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — MaryPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
102 ft
Average depth
35.1 ft
Surface area
196 acres
Shoreline
2.4 mi
Littoral zone
42%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
23 sq mi
HydroLAKES / HydroSHEDS
Elevation
988 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Mary 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 Mary Lake
Compare lakeside cabins, hotels, and vacation rentals near Mary 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.
Top-rated places to stay near Mary Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Fish Species
Click a species to see every lake where it is documented.
Fishing Mary 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: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Ice season
Typical ice-out
Apr 4
Earliest Mar 8, 2017 · Latest Apr 23, 2008
Most recent ice-out
Mar 8
2017
7 observations · Minnesota PCA ice records
EPA Impairment Status
Mary 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.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN86-0156-00 · Official waterbody report
Nearby Lakes in Wright County
Frequently asked questions about Mary Lake
Where is Mary Lake?
- Mary 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 Mary Lake?
- Mary Lake in Wright County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5 ft visibility. Maximum depth: 102 ft. Surface area: 196.03 acres.
Is Mary Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Mary Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), mercury. Check local advisories before you swim.
What is the water temperature of Mary Lake?
- Mary Lake typically sits around 57°F at the surface in October, from 134 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.
How deep is Mary Lake?
- Mary Lake has a maximum depth of 102 feet and an average depth of 35.1 feet. The lake covers 196.03 acres.
What fish are in Mary Lake?
- Fish species found in Mary Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, yellow bullhead, yellow perch. Mary Lake is located in Wright County, Minnesota.
What did the DNR fisheries survey find at Mary Lake?
- Minnesota DNR's Standard Survey on August 14, 2017 caught 2.00 walleye per gill net at Mary Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Mary Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
When does Mary Lake thaw?
- Mary Lake typically has ice-out around Apr 4.
Are there boat ramps on Mary Lake?
- Mary Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Mary Lake. Public access is listed as yes.
Can I fish at Mary Lake?
- Mary 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 Mary Lake across LakeQuality
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Where this data comes from
50 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
MNPCA50 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
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