Lake Gratiot
Keweenaw County, Michigan1,453 acresView mapDirections
EGLE publishes the water-quality measurements for Lake Gratiot. Here is what has been measured.
- 70 ft max depth
- Public access
- Limited data
Lake Gratiot in Keweenaw County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 16.5 ft visibility. Maximum depth: 70 ft. Surface area: 1453.1 acres.
Free interactive depth-contour map of Lake Gratiot, reaching a maximum surveyed depth of 70 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Michigan DNR.
Lake Gratiot is a 1,453-acre lake in Keweenaw County, Michigan with a maximum depth of 70 feet. Water clarity is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2022-09-13. Methodology: how these readings are compared.
Lake Gratiot covers about 1,500 acres in Keweenaw County. It has one public boat landing. Vrbo is where to look for cabins and lake homes around Lake Gratiot, and Booking.com and Expedia search hotels near the lake for your dates.
What Lake Gratiot is good for
From access and monitoring records, not editorial picks.
- Clear water16.5 ft of visibility
- Boat launch1 documented ramp
- Deep water70 ft surveyed max depth
- Big water1,453 acres
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Lake Gratiot 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 Lake Gratiot
These are the measurements EGLE publishes for Lake Gratiot, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 16.5 ft down. TSI 37.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 16.5ft | 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. | 37 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Lake Gratiot
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
70 ft
Surface area
1,453 acres
Public access
Yes
Listed by EGLE
Recreation & Access
- Gratiot 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 Lake Gratiot
Compare lakeside cabins, hotels, and vacation rentals near Lake Gratiot in Keweenaw County, Michigan — 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 Lake Gratiot
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Follow Lake Gratiot’s readings
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Fishing Lake Gratiot
Water Quality Trend: Stable
Based on 7 years of monitoring (2016–2023).
Water clarity
Improving7 years
Phosphorus
Worsening+0.54 µg/L/yr7 years
Nearby Lakes in Keweenaw County
Frequently asked questions about Lake Gratiot
Where is Lake Gratiot?
- Lake Gratiot is a lake in Keweenaw County, Michigan. Its water-quality measurements are published by EGLE and shown on this page as reported.
What is the water quality of Lake Gratiot?
- Lake Gratiot in Keweenaw County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 16.5 ft visibility. Maximum depth: 70 ft. Surface area: 1453.1 acres.
Is Lake Gratiot safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Lake Gratiot?
- Lake Gratiot has a maximum depth of 70 feet. The lake covers 1453.1 acres.
Are there boat ramps on Lake Gratiot?
- Lake Gratiot has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Gratiot Lake. Public access is listed as yes.
Can I fish at Lake Gratiot?
- Lake Gratiot 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 Lake Gratiot across LakeQuality
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Where this data comes from
72 measurements from 1 monitoring station, 2016–2022. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- North American Lake Management Society
NALMS72 samples · 2016–2022
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