Mary Lake
Dickinson County, Michigan230 acresView mapDirections
EGLE publishes the water-quality measurements for Mary Lake. Here is what has been measured.
- Oligotrophic
- Public access
- Limited data
Mary Lake in Dickinson County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 14.5 ft visibility. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Surface area: 230 acres.
Mary Lake is a 230-acre cold, clear oligotrophic lake in Dickinson County, Michigan. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 8 other monitored lakes in Dickinson County, Mary Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2022-09-05. Methodology: how these readings are compared.
What Mary Lake is good for
From access and monitoring records, not editorial picks.
- Clear water14.5 ft of visibility
- Boat launch1 documented ramp
Swimming conditions
Readings onlyLimited data
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. Check local advisories before you swim.
Whether Mary Lake is safe to swim in today is a call for the Michigan Department of Environment, Great Lakes, and Energy (EGLE) 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 EGLE 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.
Good clarity, visible to about 14.5 ft. Phosphorus 8 µg/L. Chlorophyll-a 1.8 µg/L. TSI 36.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 14.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 8µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.8µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 36 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Mary Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
230 acres
Public access
Yes
Listed by EGLE
No bathymetric survey has been published for Mary Lake, so its depth is not documented here.
Recreation & Access
- Lake Mary ParkPublic
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
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Fishing Mary Lake
Water Quality Trend: Worsening
Based on 6 years of monitoring (2016–2022).
Water clarity
Stable6 years
Phosphorus
Worsening+0.96 µg/L/yr4 years
Reservoir Info (USACE NID)
Mary Lake is a man-made reservoir impounded by the Mary Lake Dam, built primarily for other on the Hamilton Creek; concrete-type dam, 7 ft tall and 237 ft long.
- Surface area
- 230 ac
- Normal storage
- 350 ac-ft
- Max storage
- 764 ac-ft
- Drainage area
- 15.1 sq mi
- Hazard class
- Low
- Owner
- Waucedah Township
Source: USACE National Inventory of Dams, NID ID MI01247 · Operator website · Matched by proximity (0.24 km)
Nearby Lakes in Dickinson County
Frequently asked questions about Mary Lake
Where is Mary Lake?
- Mary Lake is a lake in Dickinson County, Michigan. Its water-quality measurements are published by EGLE and shown on this page as reported.
What is the water quality of Mary Lake?
- Mary Lake in Dickinson County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 14.5 ft visibility. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Surface area: 230 acres.
Is Mary Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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 Lake Mary Park. 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 Michigan's fish and wildlife agency, so check its current regulations before you go.
Explore Mary Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
7.3 mi away
Fish species and the cleanest lakes across Michigan
Fish species and best lakes in Dickinson County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Upper Peninsula area
Where to stay at Michigan's top lakes, each with its readings
Michigan's cleanest lakes, ranked on agency measurements
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Oligotrophic Lakes in Michigan
Where this data comes from
76 measurements from 1 monitoring station, 2016–2022. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- Michigan EGLE - MiCorps
21MICH_MICORPS76 samples · 2016–2022
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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
Named boat-access points from the USGS National Boat Ramps inventory