Thompson Lake
St. Joseph County, Michigan150 acresView mapDirections
No nutrient or algae sampling on record from EGLE for this lake.
- Impaired · Mercury
- 25 ft max depth
- Public access
Thompson Lake in St. Joseph County, Michigan has water-quality measurements published by EGLE, shown here as reported. Maximum depth: 25 ft. Surface area: 149.5 acres.
Water clarity at Thompson Lake
Clear water. Across summers from 2018 to 2023, Thompson Lake averaged 3.25 m (11 ft) of visibility down into the water, so you can typically see several feet down in midsummer. This lake sits close to the line between clarity classes, so treat the label as approximate and the depth reading as the real number.
Nobody has taken a water sample here that we can find. Michigan's environmental agency measures clarity on lakes like this one from satellite images instead, which is why this page reports how clear the water is and no phosphorus or algae readings.
Clear is not the same as clean. A lake can be easy to see through and still carry high nutrient levels, and a naturally tea-stained lake can be perfectly healthy. The nutrient and algae readings on other lakes come from phosphorus and chlorophyll-a measured in a laboratory, and clarity alone cannot stand in for them.
The same satellite images put summer algae here at roughly 4.09 micrograms per litre. Estimating algae from orbit is far less exact than measuring clarity, so that figure is worth knowing and is not part of any rating.
Thompson Lake is a 150-acre lake in St. Joseph County, Michigan with a maximum depth of 25 feet (12-foot average). Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, EGLE. Methodology: how these readings are compared.
What Thompson Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
No readingNot rated
Nutrient and algae readings are not a swimming clearance. Thompson Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Thompson 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 Thompson Lake
These are the measurements EGLE publishes for Thompson Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. TSI undefined.
Ask about Thompson Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
25 ft
Average depth
12 ft
Surface area
150 acres
Shoreline
0.8 mi
Public access
Yes
Listed by EGLE
Recreation & Access
- Thompson 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 Thompson Lake
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Fishing Thompson Lake
EPA Impairment Status
Thompson Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MI040500010808-03 · Official waterbody report
Nearby Lakes in St. Joseph County
Frequently asked questions about Thompson Lake
Where is Thompson Lake?
- Thompson Lake is a lake in St. Joseph County, Michigan. Its water-quality measurements are published by EGLE and shown on this page as reported.
What is the water quality of Thompson Lake?
- Thompson Lake in St. Joseph County, Michigan has water-quality measurements published by EGLE, shown here as reported. Maximum depth: 25 ft. Surface area: 149.5 acres.
Is Thompson Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Thompson Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
How deep is Thompson Lake?
- Thompson Lake has a maximum depth of 25 feet and an average depth of 12 feet. The lake covers 149.5 acres.
Are there boat ramps on Thompson Lake?
- Thompson Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Thompson Lake. Public access is listed as yes.
Can I fish at Thompson Lake?
- Thompson 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 Thompson Lake across LakeQuality
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Where this data comes from
Measurements for Thompson Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Named boat-access points from the USGS National Boat Ramps inventory