Cosgrove Lake
Florence County, WisconsinView mapDirections
Wisconsin DNR publishes the water-quality measurements for Cosgrove Lake. Here is what has been measured.
- Limited data
Cosgrove Lake in Florence County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 9.4 ft visibility.
Cosgrove Lake is a lake in Florence County, Wisconsin. Overall water quality is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-20. Methodology: how these readings are compared.
For a place on the water, look through cabin and lake-house rentals near Cosgrove Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Cosgrove Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Cosgrove Lake
These are the measurements Wisconsin DNR publishes for Cosgrove Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 9.4 ft. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9.4ft | 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. | 45 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Fishing Cosgrove Lake
Water Quality Trend: Improving
Based on 7 years of monitoring (2020–2026).
Water clarity
Improving7 years
Nearby Lakes in Florence County
Frequently asked questions about Cosgrove Lake
Where is Cosgrove Lake?
- Cosgrove Lake is a lake in Florence County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Cosgrove Lake?
- Cosgrove Lake in Florence County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 9.4 ft visibility.
Is Cosgrove Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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Where this data comes from
4 measurements from 1 monitoring station, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX4 samples · 2022–2025
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.