Thompson Lake
Sherburne County, Minnesota84 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Thompson Lake. Here is what has been measured.
- 22 ft max depth
- Limited data
Thompson Lake in Sherburne County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10 ft visibility. Maximum depth: 22 ft. Surface area: 84.34 acres.
Minnesota DNR's Standard Survey on July 2, 1990 caught 7.50 northern pike per gill net at Thompson Lake. DNR survey details →
Thompson Lake is a 84-acre lake in Sherburne County, Minnesota with a maximum depth of 22 feet (10-foot average). Overall water quality is declining over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-26. Methodology: how these readings are compared.
What Thompson Lake is good for
From access and monitoring records, not editorial picks.
- Clear water10 ft of visibility
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Thompson 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 Thompson Lake
These are the measurements Minnesota PCA 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.
Good clarity, visible to about 10 ft. TSI 44.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 10ft | 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. | 44 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Thompson Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Thompson Lake typically sits around 67°F at the surface in October. Summer average is about 79°F. Usually warmest in Jul (about 81°F) and coldest in May (about 67°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (67°F) to its warmest (81°F).
Typical surface water temperature by month, from 71 field readings (2010–2025) via the EPA Water Quality Portal. See the full Thompson Lake water temperature breakdown →
Minnesota DNR's Standard Survey on July 2, 1990 caught 7.50 northern pike per gill net at Thompson Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Thompson 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
2 surveys on file from MN DNR Fisheries. Most recent: 1990-07-02 (Standard Survey).
2 surveys on file · most recent 1990-07-02 (Standard Survey)
36 years old| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 78.31 | 0.18 lb | |
| Northern Pike | 8.75 | 1.27 lb | |
| Hybrid Sunfish | 6.63 | 0.11 lb | |
| Pumpkinseed | 5.17 | 0.14 lb | |
| Brown Bullhead | 2.38 | 0.54 lb | |
| Black Crappie | 2.00 | 0.25 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.
From the 1990-07-02 survey
Thompson Lake is an 84-acre lake in Sherburne County four miles northwest of the City of Big Lake. The lake has a maximum depth of 22 feet with an average depth of 10 feet. A standard survey was completed in 1990 to update fisheries data last collected in 1978. Northern Pike were sampled at a rate of 7.5/gill net,…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Thompson Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — ThompsonFisheries Lake Survey · MN DNR LakeFinder
Lake Details
Max depth
22 ft
Average depth
9.6 ft
Surface area
84 acres
Shoreline
2.1 mi
Littoral zone
75%
Share shallower than 15 ft
Public access
No
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
2 sq mi
HydroLAKES / HydroSHEDS
Elevation
919 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Thompson Lake
Compare lakeside cabins, hotels, and vacation rentals near Thompson Lake in Sherburne 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 Thompson Lake
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Fishing Thompson Lake
Water Quality Trend: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Thompson Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Becker Wwtp - MunicipalBecker · 4.9 mi away · NPDES MN0025666MajorRecent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Sherburne County
Frequently asked questions about Thompson Lake
Where is Thompson Lake?
- Thompson Lake is a lake in Sherburne County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Thompson Lake?
- Thompson Lake in Sherburne County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 10 ft visibility. Maximum depth: 22 ft. Surface area: 84.34 acres.
Is Thompson Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Thompson Lake?
- Thompson Lake typically sits around 67°F at the surface in October, from 71 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Thompson Lake?
- Thompson Lake has a maximum depth of 22 feet and an average depth of 9.6 feet. The lake covers 84.34 acres.
What did the DNR fisheries survey find at Thompson Lake?
- Minnesota DNR's Standard Survey on July 2, 1990 caught 7.50 northern pike per gill net at Thompson Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Thompson 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.
Can I fish at Thompson Lake?
- Public access to Thompson Lake is listed as no on the lake record, so confirm before you make the trip. 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 Thompson Lake across LakeQuality
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Where this data comes from
101 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
MNPCA101 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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder