Cup Lake
Big Stone County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for Cup Lake. Here is what has been measured.
- Public access
- Limited data
Cup Lake in Big Stone County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.1 ft visibility.
Cup Lake is a lake in Big Stone County, Minnesota. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-08-22. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Cup 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 Cup Lake
These are the measurements Minnesota PCA publishes for Cup Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5.1 ft. TSI 54.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.1ft | 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. | 54 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Cup Lake
Answers come straight from the public measurements and survey records on this page.
Stays via Stay22
Stays near Cup Lake
Compare lakeside cabins, hotels, and vacation rentals near Cup Lake in Big Stone 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 Cup 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 →
Follow Cup Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Cup Lake
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Cup Lake under Clean Water Act (NPDES) discharge permits.
- ClintonClinton · 2 mi away · NPDES MN0023078
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 Big Stone County
Frequently asked questions about Cup Lake
Where is Cup Lake?
- Cup Lake is a lake in Big Stone County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Cup Lake?
- Cup Lake in Big Stone County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.1 ft visibility.
Is Cup Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Can I fish at Cup Lake?
- Public access to Cup Lake is listed as yes on the lake record. 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 Cup Lake across LakeQuality
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Big Stone County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Minnesota River Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
State Parks Near Cup Lake
Other Lakes in Minnesota
Eutrophic Lakes in Minnesota
Where this data comes from
2 measurements from 2 monitoring stations, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Department of Agriculture - Pesticide Monitoring
MNDA_PESTICIDE1 sample · 2022 - Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA1 sample · 2022
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (2)
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)