Thole Lake
Scott County, Minnesota119 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Thole Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- Eurasian watermilfoil
- 12 ft max depth
- Public access
Thole Lake in Scott County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 2.8 ft visibility. Phosphorus: 76.5 µg/L. Chlorophyll-a (algae): 39 µg/L. Maximum depth: 12 ft. Surface area: 118.52 acres.
Thole Lake is a 119-acre productive, nutrient-rich eutrophic lake in Scott County, Minnesota with a maximum depth of 12 feet. Overall water quality is declining over recent sampling years. The lake supports 12 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 20 other monitored lakes in Scott County, Thole Lake ranks #20 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-10. Methodology: how these readings are compared.
What Thole Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing12 species recorded
- Ice seasonIce-out around Mar 25
Swimming conditions
Readings onlyRecreation use not supported
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. Thole Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Thole 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 Thole Lake
These are the measurements Minnesota PCA publishes for Thole Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2.8 ft of visibility. Phosphorus 76.5 µg/L. Chlorophyll-a 39 µg/L. TSI 65.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 76.5µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 39µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 65 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Thole Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Thole Lake typically sits around 56°F at the surface in October. Summer average is about 76°F. Usually warmest in Jul (about 78°F) and coldest in Oct (about 56°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (56°F) to its warmest (78°F).
Typical surface water temperature by month, from 72 field readings (2010–2025) via the EPA Water Quality Portal. See the full Thole Lake water temperature breakdown →
Lake Details
Max depth
12 ft
Surface area
119 acres
Shoreline
5.2 mi
Littoral zone
100%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
2 sq mi
HydroLAKES / HydroSHEDS
Elevation
932 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Thole 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 Thole Lake
Compare lakeside cabins, hotels, and vacation rentals near Thole Lake in Scott 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Thole Lake are listed below.
Top-rated places to stay near Thole Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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 →
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Fish Species
Click a species to see every lake where it is documented.
Fishing Thole 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
Improving6 years
Phosphorus
Worsening+42.5 µg/L/yr2 years
Chlorophyll-a
Worsening+7.5 µg/L/yr2 years
Ice season
Typical ice-out
Mar 25
Earliest Mar 12, 2016 · Latest May 1, 2018
Most recent ice-out
Mar 24
2021
4 observations · Minnesota PCA ice records
EPA Impairment Status
Thole 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, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN70-0120-01 · Official waterbody report
Nearby Lakes in Scott County
Frequently asked questions about Thole Lake
Where is Thole Lake?
- Thole Lake is a lake in Scott County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Thole Lake?
- Thole Lake in Scott County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 2.8 ft visibility. Phosphorus: 76.5 µg/L. Chlorophyll-a (algae): 39 µg/L. Maximum depth: 12 ft. Surface area: 118.52 acres.
Is Thole Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Thole Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Thole Lake?
- Thole Lake typically sits around 56°F at the surface in October, from 72 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Thole Lake?
- Thole Lake has a maximum depth of 12 feet. The lake covers 118.52 acres.
What fish are in Thole Lake?
- Fish species found in Thole Lake include black bullhead, black crappie, bluegill, brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, white sucker, yellow perch. Thole Lake is located in Scott County, Minnesota.
When does Thole Lake thaw?
- Thole Lake typically has ice-out around Mar 25.
Are there boat ramps on Thole Lake?
- Thole Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Thole Lake. Public access is listed as yes.
Can I fish at Thole Lake?
- Thole 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 Thole Lake across LakeQuality
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Where this data comes from
46 measurements from 1 monitoring station, 2024–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA46 samples · 2024–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Total Phosphorus After Block Digestion
- Analysis of Chlorophyll in Periphyton and Plankton
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